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Posts Tagged ‘skin tests’

A-Z Principal Drugs (co-fluampicil - cyproterone)

Wednesday, June 24th, 2009

co-fluampicil -tablets of flucloxacillin and ampicillin
co-flumactone Tablets of spironolactone and hydrochlorothiazide.
colchicine The alkaloid obtained from meadow saffron. It is used in acute gout. Dose: 500mg every 2 hours until relief is obtained. A total dose of 10mg should not be exceeded, but relief of pain or the onset of vomiting or diarrhoea usually renders full doses unnecessary. It is also used prophylactically in doses ol’500pg 2 or 3 times a day during early treatment with allopurinol, probericcid and sulphiripyrazone. Gire is necessary in the elderly, and in renal impairment. See page 140 and’I'able 17.
corticotrophin The adrenocorticotrophic hormone of the anterior pituitary gland. It stimulates the production of corticosteroid hormones by the adrenal cortex. It is now used mainly as a test of adrenocortical function. See tetracosactrin.
Hydrocortisone.
cortisone one of the corticosteroids secreted by the adrenal cortex. Although it is rapidly absorbed orally, it is inactive until converted in the liver to hydrocortisone. It therefore has the actions, uses and side-effects of hydrocortisone, which is often the preferred corticosteroid. It should be noted that cortisone is of no value for topical application. See hydrocortisone, page 250 and Table 36.
colestipol An exchange resin used in hyperlipidaemia that acts by binding with bile salts in the gut and preventing their reabsorption, and so indirectly lowers the plasma level of cholesterol.
Dose: 10-30g daily. May interfere with the absorption of many drugs. (Colostid). See page 146 and Table 20.
colfoseeril A pulmonary surfactant used in the respiratory distress syndrome of the new-born. (Exosurf). See beractant.
colistin An antibiotic used mainly for bowel sterilization.
Dose: 4.5-9 mega-units daily. In systemic gram-negative infections 2 mega-units 8-hourly by injection have been used, but less toxic antibiotics are now preferred. Colonlycin).
collodion When applied to the skin, it dries to form a flexible film, and is used as a vehicle for the extended local application of drugs such as salicylic acid.
co-phenotrope tablets of diphenoxylate
and atropine. (Lomotil; Tropergen).
co-prenozide Tablets of oxprenolol and cyclopenthiazide. (Trasidex).
co-proxamol Tablets  and paracetamol. (Distalgesic).
corticosteroids Hormones secreted by the cortex of the suprarenal gland. The principal hormone is hydrocortisone but more potent synthetic derivatives such as dexamethasone are also in use.
co-tenidone Tablets of atenolol and chlorthaliclone. (Tenoretic).
co-triamterzide Tablets of hydrochlorothiazide and triannerine. (Diazide).
co-trimoxazole A mixture of trimethoprini and sulpliaiiietlioxazole. Trimethoprim, like the sulphonamides, interferes with the folic acid cycle of bacterial metabolism, but at a different point, and the mixture has an increased antibacterial action. It was once widely used, but is now advised only for Prieunjocystis carinii pneumonia. Occasionally given in acute bronchitis and urinary infections when no other drug is acceptable.
Dose: 120 nig/kf; daily lot- 14 days; 960 ing 12-hourly by i.v. infusion. (Bactrin); Septrin).
coumarins Compounds that depress the formation in the liver of prothrombin and other blood coagulation factors. See warfarin and phenindione.
counter-irritants Substances, also referred to as rubifacients, that, when applied to the skin, produce a mild, local irritation and inflammation, and give symptomatic relief in painful conditions of the muscles and joints. Creams and liniments containing methyl salicylate, turpentine, capsicum resin and menthol are examples of rubifacients.
crisantaspase Asparagine is an aminoacid essential for the development of some malignant cells. Crisantaspase is an enzyme, also known as asparaginase, that breaks down asparagine, and so has an indirect cytotoxic action. It is used to induce remission in acute lymphoblastic leukaemia in children.
Dose: (after pre-treatment with other drugs): 1000 units/kg by slow i.v. injection daily for 10 days. Side-effects include anaphylactic reactions, and skin tests to detect hypersensitivity
are essential before initial and re-treatment. (Erwinase).
crotamiton An ascaricide and antipruritiL. Used by local application as cream or lotion (10%) in the treatment of scabies and itching conditions. (Eurax).
crystal violet A dyestuffwith a selective action against Gram-positive organisms and yeasts. Used as a 0.5% solution for infected skin conditions, and for skin
preparation.
cyanocobalamin The anti-anaemic factor present III liver. It is specific in the treatment of pernicious anaemia and its neurological complications, and of value in some other anaernias due to nutritional deficiencies.
Dose: in pernicious anaemia, I Ing by i.m. injection at monthly intervals. It has been largely replaced by hydroxocobalamin, which has a more prolonged action. (Cytanien). See page 112 and’I'able 3.
cyclizine An antihistamine, used mainly in I ravel sickness and nausea generally. Also useful in vertigo.
Dose: 100-150 mg daily. Side-effects include dryness of the mouth, headache and drowsiness. (%Ialoid).
cyclopenthiazide A thiazide diuretic with the actions, uses and side-effects of bend roll tiazide.
Dose: I mg initially, 250-500mg daily or on alternate days, in the morning, according to need. (Navidrex). See page 148 and Table 21.
cyclopentolate An anticholinergic agent use(] to produce cycloplegia and mydriasis. The action is more rapid and less prolonged than atropine, particularly in children. (Mydrilate).
cyclophosphamide A widely used alkylating
cytotoxic agent, active orally and by injec-
tion. Used in I lodgkin’s disease, chronic
lymphocytic leukaemia and lymphomas. Dose: 100-300 Ing daily, orally or i.v., or 300 mg-1 g weekly. A high fluid intake is necessary, as a metabolite may cause hacm- ( )rrhagic cystitis, and it is sometimes used with mesna to reduce the risk of such cystitis. Nausea and vomiting are common side-effects, as is epilation with high doses. (Endoxana). See page 122 and Table 8.
cyclopropane An inhalation anaesthetic of high potency with which induction and recovery are rapid. It causes some respiratory depression and cardiac irregularities, and its administration requires care. It is used with closed-circuit apparatus as it forms an explosive mixture with air and oxygen. Supplied in orange-coloured cylinders.
cycloserine An antibiotic used in
pulmonary tuberculosis when standard drugs are ineffective. Occasionally used in urinary infections.
Dose: 250-750 mg daily. Side-effects include drowsiness, vertigo and rash. See page 170 and Table 31.
cyclosporin An antibiotic with a powerful inuininosuppressant action. It is used under expert control to prevent graft rejection in organ and bone marrow transplantation, and in the prevention of graft-versus-host disease (GVI-ID). Prolonged therapy over some months may be required. Side-effects may include tremor, gastrointestinal disturbance, hypertrichosis and nephrotoxicity (Neural; Sandinimun).
cyproheptadine A compound with antihistamine and antiserotonin properties. Sonic allergic reactions are due not only to histamine, but also to serotonin, and cyproheptadine is useful in conditions not responding completely to an antihistamine. Dose: 4-20 ing daily. It has been used as an appetile stimulant in doses of 12 mg daily and in refractory migraine. (11criactin). See page 110 and Table 2.
cyproterone An anti-androgen used to reduce libido in sexual deviants. Dose: 50-100 nig daily. It is also used in the palliative treatment of prostatic carcinoma, particularly in advanced cases that have become resistant to other therapy. Dose: 300 mg daily.

Accurate Diagnosis

Saturday, May 30th, 2009

The simplest and most certain test for any sensitivity reaction is to expose the person concerned to the substance under suspicion and see what happens. This is known as a

challenge test. With true allergies, challenge tests are powerful tools, but they are also alarmingly close to reality. The risk of provoking a severe reaction requires a very

cautious approach.
By comparison, an indirect test – a roundabout way of seeing how the body responds, such as the skin-prick test (see p. 91) – has the advantage of rarely producing dangerous

reactions. The downside is that indirect tests can be misleading, precisely because they are not like the real-life situation. No indirect test is perfect – there are always

false positives and false negatives (see box on p. 91).
Challenge tests
If you undergo a challenge test with food or an airborne allergen, you will also be given dummy challenges with an innocuous substance which is indistinguishable from the item

being tested. Neither you, nor the tester who is scoring the reaction, should know which is which. This is called a double-blind trial because, to eliminate all possible bias,

both of you are in the dark. (The full name is a ‘double-blind placebo-controlled trial’ – the dummy challenge is also called a ‘placebo challenge’ or ‘control challenge’.)
The double-blind trial is a standard medical procedure and does not imply that the doctors think you are faking symptoms. Psychological forces are powerful things, and just

thinking that you might react to a test can be enough to produce a reaction – the process that generates the symptoms is largely unconscious.
Food challenge
A food challenge – eating the food that is under suspicion – is a key test for food intolerance (see p. 197). It is sometimes used for food allergy and other forms of food

sensitivity too, as a follow-up to skin tests. Some allergists use a food challenge only if the skin test is at odds with actual events reported by the patient. Other allergists

use food challenge more readily, to confirm skin-test results, and to assess the severity of the reaction.
Extreme caution must be exercised with immediate food allergy, because of the considerable risks involved. The test must be done under medical supervision with resuscitation

equipment to hand. A challenge test should never be done for true food allergy without some careful preliminary tests on the face and the lips (see box on p. 23). Even if these

tests produce no reaction, only tiny amounts of the food should be eaten to begin with.
Bronchial challenge
This type of test involves inhalation of an airborne allergen – such as pollen – suspected of causing asthma. Bronchial challenge carries the risk of provoking a severe asthma

attack, and few doctors use it unless there are compelling reasons to do so – such as demonstrating that someone’s asthma is due to an allergen encountered at work.
Skin-prick tests
This is an indirect method of detecting true allergic reactions. It is one of a family of skin tests that use a similar approach. The three different tests in this family are

known as: skin-prick tests or prick tests, puncture tests, and scratch tests.
For the skin-prick test – the technique used in Britain – a small drop of liquid containing an allergen, such as grass pollen, is placed on the arm. The doctor makes a small

prick in the skin, under the drop of liquid, allowing a minuscule amount of the allergen to get into the skin. A positive reaction is recorded if a red bump develops soon

afterwards. For accuracy, the bump must be compared to positive and negative controls (see below).
The puncture method is very similar to the skin-prick test but uses a slightly different technique for breaking the skin. The term prick-puncture test covers both techniques.
With the scratch method, the skin is scratched lightly, and the allergen solution is then applied over the scratch. This method gives less consistent results than prick-puncture

testing.
It is important to include a negative control in the test – a skin-prick test with plain salt water (saline). This should not produce much of a bump – if it does, the skin is

clearly over-reactive and the tests more difficult to assess. The doctor should also include a positive control – a skin-prick test with histamine, the substance that plays a

central role in allergic reactions. This should always produce a bump. If it does not, the skin is decidedly under-reactive, and the tests are invalid.
Taking antihistamines will make the skin under-reactive, and you should stop taking them before the testing, for a period ranging from a day to several weeks – it varies

depending on the particular antihistamine. Ask your doctor for specific instructions about stopping these and other drugs before testing.
Skin tends to be over-reactive to testing in people with dermatographism (see p. 52). Blood tests for specific IgE,
such as RASTs (see p. 92), are needed for anyone who has this condition. Eczema sufferers with a rash over large areas of the body may also require blood tests, if there is too

little clear skin for testing.
Skin-prick tests can produce both false positives and false negatives (see box below). Some allergic diseases will give a lot of false negatives and relatively few false

positives, while for others the reverse is true. The allergen itself influences the rates of misleading reactions: for example, tests for soya allergy are notoriously

unreliable, whereas those for peanut are far more accurate. The age of the person being tested also makes a difference. With all these influences at work, interpreting the test

responses is a real art, and the doctor’s experience counts for a lot.
All sorts of people offer skin-prick tests, including alternative practitioners. Get them done by a qualified doctor, preferably by an allergist, who will know how to make sense

of the reactions.
Note that the purpose of these tests, and of blood tests for specific IgE, is to identify the allergens that are bringing on your symptoms, not to predict how strongly you will

react to those allergens. The tests may give some Indication of the intensity of your reaction, but they cannot be regarded as a good guide to how you will respond to the

allergen in the future.
The safety record of skin-prick tests is very good. Occasionally a systemic reaction (anaphylaxis) occurs with these tests, but there are no records of any deaths. Nevertheless,

if you suffer from severe asthma or have experienced anaphylactic shock in the past, it is advisable for the doctor to have adrenaline and resuscitation equipment available.

Those with strong allergic reactions to latex may also react badly if they are tested with an allergen that cross-reacts with latex (e.g. cypress pollen), not just when tested

with latex itself. Taking beta-Mockers (see box on p. 150) increases the risk of a life-threatening reaction for anyone in these higher-risk categories.
False positives and false negatives
Apart from challenge tests, none of the tests used for allergy works with 100% accuracy. Most give both false positives and false negatives.
A false positive means that there is a positive test but no actual reaction when the allergen is encountered (e.g. eaten or inhaled). A false negative means that there is a

negative test result despite a genuine reaction (as shown by a challenge test, for example).
A test that gives relatively few false positives has good positive predictive value – in other words, if it suggests you are allergic to something, you probably are.
A test that gives relatively few false negatives has good negative predictive value. If it comes up negative, you are probably not allergic to that allergen.
Some tests for allergic reactions show good positive predictive value but poor negative predictive value, while for other tests the reverse is true.

Allergy: Avoiding Milk and Lactose

Tuesday, May 26th, 2009

Avoiding Milk and Lactose
Fruit lassi
There are two quite distinct reasons for avoiding milk: either to avoid milk proteins or to avoid

lactose, the sugar found in milk. It is important not to confuse these two because the details of the

avoidance diet required are different. Only a few people need to avoid both milk proteins and lactose.
Diarrhoea and wind in response to drinking milk, but few other symptoms, usually indicates a reaction

to lactose — but a reaction to milk proteins could be an alternative explanation. If it is a reaction

to lactose, this may be due to either primary lactase deficiency or secondary lactase deficiency — your

doctor can order tests to make an exact diagnosis (see p. 79). Note that a bout of diarrhoea, however

caused, often produces a temporary lactose intolerance (secondary lactase deficiency).
Any symptoms other than (or in addition to) diarrhoea and wind strongly suggest a reaction to milk

proteins. This might be a true allergy, another type of immune reaction to milk (see pp. 72-3), or an

idiopathic intolerance reaction (see pp. 76-7). In theory, skin tests should identify true allergic

reactions to milk proteins. Unfortunately, skin tests are not infallible, and it is possible to have a

genuine allergy or other immune reaction to milk proteins, but give negative skin tests. This is

especially common with babies (see p. 65 and p. 69). There are no accurate tests that can confirm

intolerance reactions to milk proteins.
It is possible to have sensitivity to both milk proteins and lactose.
If tests do not give you a definitive answer, you may have to try both types of diet and see which one

works. Remember that lactose intolerance may be only temporary.
Avoiding milk proteins
If you have a sensitivity reaction to cow’s milk proteins, then you need to avoid:
•    milk and all milk-based drinks, including lactose-reduced milk (if you need to avoid lactose as

well, drops and tablets to reduce lactose — see Using lactase replacers, p. 183 — are safe and could be

used with a tolerated milk, e.g. goat’s milk)
•    cream, yoghurt, creme fraiche
•    all kinds of cheese, cottage cheese and cream cheese (some people may be able to tolerate

Norwegian brown cheese, called Gjetost, which is made with milk whey)
•    white sauce, bechamel sauce and other creamy sauces
•    custard, rice pudding and other milk-based puddings
•    almost all home-made cakes, biscuits, cookies, pancakes and pastry
•    some bread, rolls, waffles
•    almost all chocolate
•    casein, casemate, and lactalbumin in packaged foods (see p. 173); you may be able to tolerate

whey but experiment cautiously.
Unless your sensitivity is fairly mild, you will also need to avoid:
•    butter, except clarified butter (ghee)
•    most kinds of margarine (they generally contain milk derivatives, but
some are milk-free — health-food shops are a good source of these).
As long as you do not have a severe allergy to milk, you should be able to tolerate clarified butter.

Make this by melting butter over a low heat, pouring it into a glass jar, and leaving it to cool in the

refrigerator. The milk proteins will settle to the bottom, and be visible as whitish granules — only

eat the clear butter above this level.
Alternatively, put olive oil into a wide-necked container and place in the freezer. It will solidify,

and can be used as a spread in place of butter.
A few of those with cow’s-milk allergy can tolerate sheep’s milk, and possibly (but less commonly)

goat’s milk. However, most people must avoid these as well. (There are also rare individuals who are

allergic to goat’s and sheep’s milk but not to cow’s milk.) Ass’s milk, if you can get it, is tolerated

by most with cow’s-milk allergy. There are many substitutes for cow’s milk now available, such as soya

milk, almond milk, rice milk and hazelnut milk. Try a health-food shop for these. All can be used in

place of ordinary milk when cooking.
Margarine or clarified butter can be used in recipes that call for butter. Soya yoghurt and cream make

reasonable substitutes for ordinary yoghurt and cream.
Avoiding lactose
If you have lactose intolerance, you must avoid:
•    milk and all milk-based drinks, unless lactose-reduced
•    cream, creme fraiche
•    most kinds of yoghurt, especially mild yoghurt. A very strong, acidic yoghurt may contain

little lactose. The bacteria that make yoghurt turn lactose into lactic acid, so the more acidic it is,

the less lactose it contains.
•    cottage cheese and Norwegian brown cheese, or Gjetost. Other kinds of cheese are usually so low

in lactose that they are tolerated. Only those people with extreme lactose intolerance need to avoid

all cheeses.
•    white and bechamel sauce, custard, rice and other milk-based puddings
•    almost all home-made cakes, since milk is generally used for baking. Items cooked with butter

but not milk, such as biscuits, cookies and pastry, are usually tolerated, as is butter itself, and all

margarine.
•    lactose in medicines. Lactose powder is used in many tablets and capsules, just to bulk out the

drugs. The amount used can be sufficient to evoke symptoms in some people with lactase deficiency.

Certain asthma inhalers also contain lactose (see p. 162), and a small amount may be swallowed. The

lactose from inhalers will affect you only if you have severe lactase deficiency.
Soya-based products, and all other nut- or grain-based milk substitutes, are lactose-free. Sheep’s

milk, goat’s milk and other animal milks (including human breast milk) all contain lactose.
Using lactase replacers
Many people with lactose intolerance are able to eat a more varied diet by using lactase replacers.

These provide a temporary supply of the missing enzyme, lactase (see p. 79), which helps out by

digesting the lactose in milky foods. Lactase replacers must be taken at the same time as the milky

food, and are only effective for that one meal. The more lactose there is in the meal or snack, the

more of the lactase replacer you need – trial and error is the only way of working out how much you

need for a particular food. There are a number of different brands of lactase replacer now available,

and it is worth trying out several. Some people find that they are sensitive to an added ingredient in

some brands. Sources of lactase replacers include health-food shops and specialist suppliers – these

can be located through the Internet (see p. 255).
Savoury white sauce
Savoury white sauce is the base of many dishes. Here the flavour of the wine and stock goes well with

chicken, vegetables or fish.
PREPARATION TIME: 7-8 minutes MAKES: approx. 600ml (1 pint)
50g (13/4oz) milk-free baking margarine 50g (1314oz) plain flour
200ml (7fl oz) dry cider or dry white wine 400ml (14f1 oz) vegetable or chicken stock 1 bay leaf, salt

and pepper
Melt the margarine in a small saucepan and stir in the flour. Cook, stirring, over a low heat for
1 minute then stir in the cider or wine, followed by the stock. Add the bay leaf and simmer, stirring

occasionally, for 5 minutes until thickened. Season to taste.
Variations. add approx. 6 tbsp finely chopped herbs, e.g. parsley, chives, tarragon or chervil; or add

English or French mustard; or add lemon juice.
Sweet white sauce
PREPARATION TIME: 5 minutes MAKES: approx. 300ml (’/?pint)
2 tbsp cornflour
25g (1 oz) caster sugar
300ml (V2 pint) apple or white grape juice 4 tbsp soya cream
25g (1oz) milk-free margarine
In a saucepan, mix the cornflour and sugar with a little of the juice to give a smooth paste then

gradually stir in the rest of the juice and bring to a simmer over a low heat. Simmer for 1-2 minutes

until thickened, stirring all the time. Finally, add the soya cream and margarine.
Variations: melt in 1008 (3-/2oz) or more of milk-free chocolate; or add rum or brandy to taste; or add

4-6 pieces finely chopped stem ginger together with 1-2 tbsp of their syrup.
Pancakes
Soya milk has a slightly thicker consistency than cow’s milk and therefore more is used in this pancake

recipe than would be needed in a traditional one.
PREPARATION TIME: 25 minutes MAKES: approx. 16 small pancakes
150g (5V2oz) plain flour, sieved 2 large eggs
pinch salt
450ml (16f1 oz) soya milk
oil or milk-free margarine for frying To serve:
lemon juice and caster sugar or golden syrup
Combine the flour, eggs, salt and soya milk in a liquidiser until smooth. Alternatively place the

flour, eggs and salt in a bowl and slowly whisk in the soya milk to form a thin batter.
Heat approx.1 tsp oil or margarine in an 18cm (7in) non-stick frying pan and swirl until hot. Pour in

sufficient batter to just cover the base of the pan and cook until golden. Turn and cook on the other

side until golden.
Serve with lemon juice and caster sugar or with golden syrup.
Apple and frangipane tart
An alternative to a milk-based custard tart. The combination of apple and almond is delicious. Serve

freshly baked. It can also be eaten cold, but if possible, warm it a
little before serving.
PREPARATION TIME: 30 minutes COOKING TIME: 1-11/4 hours MAKES: 8 servings
Pastry:
175g (6oz) plain flour, sieved
1008 (3 V2oz) milk-free baking margarine, softened
25g (1 oz) caster sugar
Filling:
50g (13/4oz) milk-free sunflower margarine 1008 (3112oz) ground almonds
100g (3112oz) plus 1 tbsp caster sugar 2 egg yolks
2 tbsp dark rum, brandy or orange juice 2 large dessert apples
4 tbsp apricot jam
Work the flour, margarine and sugar together with 1 tbsp cold water to make a soft dough. Roll out and

use to line a deep 20cm (8in) fluted flan tin. Chill this while you prepare the filling.
Preheat the oven to 190′C/375′F/gas mark 5. Beat together the margarine, ground almonds, 100g (3Y2oz)

caster sugar, egg yolks and rum. Peel, core and roughly chop one apple and stir into the mixture.

Spread this in the pastry case. Core and thinly slice the remaining apple and arrange the slices on

top. Sprinkle with the remaining sugar and bake for 1-1′/’4 hours until risen and golden. Cool slightly

then brush the surface with the apricot jam (warm this gently in a saucepan first).
Coconut rice pudding with mango
This pudding is based on a Thai recipe. The rice pudding will become thicker the longer it cooks and

also as it cools. Make sure the mango is ripe.
COOKING TIME: 30-40 minutes MAKES: 6 servings
175g (6oz) pudding rice, rinsed 50-75g (131-2314oz) sugar
1 litre (13/4 pints) carton rice milk 400ml (14f1 oz) coconut milk To serve:
1 extra-large ripe mango, peeled and diced
toasted coconut shreds
Place the rice in a large saucepan with 50g (13/4oz) of the sugar and the rice milk and coconut milk.

Bring to a simmer, stirring. Simmer gently for 30-40 minutes, stirring occasionally, until the rice is

cooked and the milk absorbed. Add the extra sugar if wished. Serve warm or cold, topped with mango and

toasted coconut.
Baked strawberry creams with strawberry sauce
The riper the strawberries the better, to give intensity to both the creams and the sauce.
PREPARATION TIME: 30 minutes COOKING TIME: 20-25 minutes MAKES: 6
1008 (3112oz) caster sugar
4 tbsp Muscat wine
1 tsp lemon juice
350g (12oz) strawberries, hulled and sliced
4 large eggs, beaten Sauce:
225g (Boz) strawberries, hulled and chopped
2 tbsp icing sugar 2 tbsp Muscat wine To serve:
a few whole strawberries
Preheat the oven to 1 70′C/325′F/gas mark 3. Set six 1 50ml (Y4 pint) ramekins in a small roasting tin.

If you plan to unmould the creams, oil the ramekins lightly.
Place the sugar, wine, lemon juice and strawberries in a saucepan and heat gently to dissolve the

sugar. Bring to the boil and cook, uncovered, for 5 minutes. Cool slightly then puree in a liquidiser

and whisk into the beaten eggs. Pass through a sieve then pour into the ramekin dishes.
Pour hot water from a kettle around the ramekins and cook in the centre of the oven for 20-25 minutes

until lightly set.
Remove the dishes from the tin and allow to cool. Chill, if wished.
Combine all the sauce ingredients and liquidise until smooth. Pass through a fine sieve.
Serve the creams in the ramekins with a little sauce poured on top and decorated with a whole

strawberry, or carefully unmould, pour a little sauce over, then decorate with a whole strawberry.
Variation: oil the ramekins. Dissolve 100g (31/2oz) caster sugar in 4 tbsp water in a small saucepan

over gentle heat, then cook to a rich caramel without stirring. Pour a little caramel into each oiled

ramekin then continue as above. Pour the wine for the sauce into the pan used to make the caramel and

warm gently to dissolve any leftover caramel, then continue with the sauce as above.
Frozen vanilla dessert
This is a cross between a sorbet and an ice cream.
PREPARATION TIME: 30 minutes, plus freezing MAKES: 4-6 servings
1 vanilla pod, split
150g (51/2oz) caster sugar 500g carton soya yoghurt
Place the vanilla pod and sugar in a saucepan with 300ml (1/2 pint) water. Dissolve over gentle heat

then bring to a simmer and simmer for 20 minutes. Leave to cool then remove the pod, scraping all the

seeds from it and returning them to the syrup. Beat in the soya yoghurt and freeze.
You will get the best texture by using an ice-cream machine. Alternatively, freeze in a plastic

container then remove from the freezer and beat the mixture well until smooth (you can do this in a

food processor). Return to the freezer. Repeat this process once or twice.
Baked strawberry cream with strawberry sauce
Variations: add 100g (31/2oz) melted plain chocolate; or add 2 tbsp instant espresso coffee dissolved

in 2 tbsp hot water. Alternatively, dissolve 100g (3/2oz) caster sugar over a gentle heat in a small

saucepan until it turns to a rich caramel; then add 100g (31/2oz) unblanched almonds and stir with a

metal spoon until they start to pop. Transfer to an oiled tray and leave to set. Crush roughly and add

to the basic mixture.
Fruit lassi
This refreshing Indian drink can also be made with frozen fruit, in which case don’t use iced water –

cold will do.
PREPARATION TIME: 10 minutes
MAKES: approx. 1.35 litres (21/4 pints)
500g carton soya yoghurt
50-75g (1314-231aoz) sugar
225g (8oz) berries such as raspberries, strawberries, blackberries or blueberries or the equivalent

weight of chopped fruit such as mango, peach or papaya
600ml (1 pint) iced water
Place all the ingredients in a liquidiser and blend until smooth.
Frozen vanilla desert
Banana and strawberry shake
A special treat for a child who cannot have milk.
PREPARATION TIME: 5 minutes MAKES: 600ml (I pint)
2 large, very ripe bananas
150g (5112oz) strawberries
1112 tbsp olive oil
a little nutmeg or other spice, if liked 200ml (7fl oz) water
Peel the bananas and roughly chop the fruit. Combine all the ingredients in a blender until very

smooth. Serve immediately, or cover tightly and store in the refrigerator.
Variations: use a nectarine or a skinned peach instead of strawberries; use coconut milk (available in

tins) instead of olive oil, and the flesh of a small mango, or half a large mango, instead of

strawberries.

Elimination Diet against Allergy

Monday, May 25th, 2009

Elimination diet
An elimination diet is a method of diagnosing idiopathic food intolerance (see p. 74) and certain other

forms of food sensitivity where indirect tests, such as skin tests, are unhelpful. The principle of the

elimination diet is very simple. It begins by removing from the body every food that could possibly

cause a reaction, and seeing if this produces a symptom-free state. If it does, the elimination diet

then presents the body with different foods, each in its pure form, to see which ones cause symptoms.
While the principle is simple, the practicalities of the elimination diet can be much more complex, and

it is vital to understand the details fully before you start. There is absolutely no room for

‘cheating’ with this diet – one mouthful of cake is enough to ruin the whole thing. You need forward

planning and a lot of self-discipline, backed up by a good stock of the permitted foods for moments

when hunger overcomes you. Some cooked foods, stored in the freezer in individual portions for quick

defrosting, are a great help.
Doing an elimination diet incorrectly is not just a waste of time. Some people acquire new

sensitivities during the diet, which may make it very much more difficult to do a second elimination

diet. So plan ahead and get it right first time.
The planning stage
First of all, start an accurate symptom diary. This will give you a precise picture of how bad things

are now, before you try any dietary measures. A detailed daily symptom record, covering a period of

about two weeks, can be very useful, whether or not you actually do an elimination diet. It can serve
as a baseline against which to judge the effects of any future treatment.
Before you begin an elimination diet, you must see your doctor and ask if it is safe for you to do the

diet. Read through the next four pages first – the more you know about elimination diets, before

talking to your doctor, the better.
There are some conditions where, although an elimination diet can be very helpful, it should not be

attempted without full medical supervision. Two main causes for concern exist:
•    For people who are undernourished to start with, the elimination diet may be too demanding – it

is difficult to eat enough calories during the first few weeks of the diet, unless an elemental diet is

used as a supplement (see box on p. 196). If you are underweight, or have rheumatoid arthritis or

Crohn’s disease, the possible use of elemental diets is something you should discuss with your doctor.
•    With certain diseases (see list that follows), the testing stage may induce severe symptoms.

Sometimes these can be life-threatening and need immediate medical attention.
Medical supervision during food testing is recommended for anyone with these conditions:
•    Crohn’s disease – testing can bring on a prolonged relapse. Very small amounts of food should

be tested initially, and the quantity slowly increased.
•    Brittle asthma – after a period of avoidance, a culprit food can bring on a severe and possibly

life-threatening asthma attack.
•    Atopic eczema – the risk of reactions is higher if skin tests are positive (see p. 198).
•    Chronic urticaria – occasionally there is an immediate reaction to an offending food. It is

advisable to test foods in very small portions oust a mouthful) at first. If there is no reaction

whatever after four hours, a normal portion can be tested.
Note that an elimination diet is not suitable for anyone with true food allergy (see p. 62). If you

have ever had an immediate reaction to any food, or any symptoms in the lips or mouth, testing foods

can be dangerous. Caution is also necessary if you have ever reacted to a food with violent vomiting

and/or diarrhoea some hours after eating. This could be due to an infection, of course, but such

symptoms can also, very rarely, result from true food allergy (see p. 64). Finally, if you have ever

suffered anaphylaxis from any cause – not just food –the testing phase of an elimination diet might be

risky. Ask your doctor’s advice.
Once you have your doctor’s permission to try the diet, work out how the stages of the diet will fit in

with your life over the weeks or months ahead. Until it is over, eating food made by other people is

virtually out of the question. When eating away from home, you must either take prepared food with you,

or just eat very simple foods – such as permitted fruits or nuts. Think about the practicalities of

carrying food for meals away from home.
Finally, devise the diet you will follow during the exclusion phase (see right), locate shops that sell

the more unusual foods, and stock up on everything required.
You will continue to eat a lot of these foods for the first few weeks of the testing stage, so you may

want to buy extra stocks and refrigerate them for
longer storage, especially if the sources of supply are some distance from your home.
Note that food ingredients in medication could interfere with the results of the elimination diet. For

example, if you are very sensitive to maize (corn), the cornflour that is added to many antihistamines

and other drugs could create much confusion. Food-free medicines are available – talk to your

pharmacist about this initially, then to your doctor if you need a different prescription.
The exclusion phase
During the first part of an elimination diet, you exclude all the foods that you normally eat, plus any

closely related foods. For example, if you normally eat oranges, you should avoid all other citrus

fruits, including lemon, limes and grapefruit, even though you do not normally eat these. If you

normally eat plenty of broccoli, you should omit all its relatives, such as cabbage, kale, spring

greens and cress.
The best way to conduct the exclusion phase is not to follow a set menu, such as the well-known

‘Iamb-and-pears’ diet, but to draw up your own list of permitted foods. This can include foods that you

have never eaten before, and those you eat rarely.
The list should run to at least ten items. One problem with an exclusion phase that consists of only

two foods (as in the ‘Iamb-and-pears’ diet) is that you are bound to eat a huge amount of these foods.

This is asking for trouble if you have a tendency to food intolerance, because you can quite quickly

become sensitive to new foods if eating them in large amounts.
Your list of permitted foods should include:
Some starchy items. These are essential for keeping hunger at bay: try some of the more exotic root

crops, such as sweet potatoes, yams, dasheen and cassava. These are available in large supermarkets and

in small shops catering to Indian, African, Chinese and Caribbean communities. (Cook them as you would

potatoes. In the case of cassava, it must be boiled, not baked.) You can also eat parsnips, turnips,

chestnuts and pumpkin. Tapioca, sago, buckwheat, millet, quinoa and sorghum are other possibilities: a

health-food shop is a good source of some of these. Use rice if it is not normally part of your diet.

Do not include sweetcorn or maize meal, even though you do not normally eat these –corn products are

very widely used in packaged food, and sensitivity to corn is not uncommon.
Several fruits and vegetables that you don’t normally eat. Exotic produce such as mangoes and okra can

help a lot in keeping the diet tasty. Avocados, which are very rich and nutritious, can be included if

you don’t eat them often.
Some protein items. For carnivores, this is the easy part – any meat that you don’t normally eat is

suitable. Consider turkey, rabbit, pigeon or game, for example. (Soak rabbit meat in salt water

overnight to get rid of the strong taste, if you dislike this.) Strict vegetarians have more problems

here, since goat’s milk, sheep’s milk and all birds’ eggs are disallowed – their proteins are much too

similar to those of normal milk and eggs. Soya products such as tofu should definitely be avoided, as

should other pulses initially, because sensitivity to these is a possibility among vegetarians. Quorn,

or mycoprotein, could affect anyone sensitised to yeast, and should not be included. Fortunately the

exclusion phase is fairly brief, so a low intake of protein will not be disastrous. Including some nuts

on your list of permitted foods will help, as these contain protein. If nuts are part of your normal

diet, you may have to resort to rarely eaten kinds such as macadamias, cashews or pistachios.
Elemental diets
An elemental diet is a powder that contains all the nutrients the human body needs but is free from the

substances in food that provoke allergic and intolerance reactions. It is mixed with water to create a

complete substitute for food. Originally designed for space travel, this totally synthetic form of

sustenance is also known as ‘the astronaut’s diet’.
Used alone during the exclusion phase, elemental diets are the basis for the ultimate – and

theoretically foolproof – elimination diet. They sustain you through the exclusion phase, and continue

to provide your basic diet during the testing phase.
For anyone with multiple food sensitivity, using an elemental diet circumvents the problem of finding

ten or more safe foods with which the elimination diet can begin.
Those who are underweight can also benefit from using an elemental diet, simply as a calorie-boosting

supplement during the exclusion phase and testing phase.
Unfortunately, elemental diets taste fairly unpleasant and are quite expensive. You
may need a prescription, so talk to your doctor. Ideally you should get an elemental diet that does not

contain sucrose (sugar).
Some items that make good snacks. Nuts, pumpkin seeds, sunflower seeds, fresh fruit and dried fruit are

all useful for times when you are away from home, or feel hungry between meals. At the outset of the

diet, use only unsulphured dried fruit –available from health-food shops. At a later stage, you can

test ordinary dried fruit (all of which is treated with sulphur preservatives – see box on p. 207).
A cooking oil, preferably one that you have not used much in the past. Use this fairly liberally, to

keep the calorie content of your diet at a reasonable level
Note that this is a very plain diet – you eat the permitted foods and absolutely nothing else. You

cannot use spices, herbs or other flavourings. Salt is allowed, but sugar is out, as are tea, coffee,

alcohol and all soft drinks. You must drink only mineral water and pure juices from permitted fruits.
Don’t use canned or packaged versions of the permitted foods. Buy raw food and cook it yourself. The

idea is to avoid food additives and other contaminants, such as those from the linings of cans.
Throughout this phase, and the next, you must be very careful not to eat too much of any one food.

Never eat any food every day, and stay away from any food that you begin to develop a real passion for

– this is always a bad sign in people with food intolerance. It is better to go a little hungry

(assuming you are not underweight to start with) rather than binge on any of the permitted foods.

Acquiring new sensitivities is all too easy.
Assuming you do have food intolerance, and you have excluded all the foods that affect you, there

should be a complete clearance of symptoms within 7-10 days. The response is usually unmistakable. A

partial or slight response is probably just a coincidence, and should be discounted, except for those

with rheumatoid arthritis (see below).
Be warned that you may feel a great deal worse before you get better. For those who do have idiopathic

food intolerance, the first 5-6 days of the diet can be very unpleasant – usually they suffer the same

symptoms as before the diet, but far more severe.
Some conditions, such as Crohn’s disease and rheumatoid arthritis, may require a longer exclusion

phase, but there is no point in continuing beyond three weeks. Bear in mind that long-term structural

damage to arthritic joints may prevent a complete recovery. A partial but sustained improvement in the

joints, accompanied by a distinct improvement in general health, suggests that food could well be

playing a part in causing the disease, and that it is worth going on to the testing phase.
Symptoms that are only intermittent, such as chronic urticaria or migraine, pose a special problem. You

need to decide, before starting the diet, how long the exclusion phase should continue in order to give

you a clear sign that your state of health is improved. A symptom diary is vital here. If, for example,

your symptom diary shows that you sometimes have a week that is symptom-free but you never get through

two weeks without an attack, then your exclusion phase should continue for two weeks.
You should only go on to the testing phase if you improve during the exclusion phase. If you do not

improve, you have excluded the possibility of food intolerance, and can give up the diet.
The testing phase
This part of the diet, which is sometimes called the reintroduction phase, takes about eight weeks. It

requires careful observation of your symptoms, and constant self-discipline about everything you eat.

You should not stop or delay the testing unless you are ill – it is vitally important to complete it as

quickly as possible.
Foods have to be reintroduced one at a time, with a space between in which symptoms can be observed. It

sounds simple, but this is where errors can easily occur.
During this phase, as well as noting your symptoms daily, you should also record absolutely everything

you eat.
For the first 2-3 weeks you should test foods that are unlikely to cause symptoms. Start by testing

fruits, vegetables and meats that you do not eat very often normally, but which you do like. If they

pass the test, you can use them to vary your diet. This will make life much easier and reduce the risk

of developing new sensitivities.
Next test foods that you do eat reasonably often, but not every day. Leave the most likely culprits –

the foods you eat very regularly, such as wheat and milk products – until you have established a safe

diet that contains at least 25 different foods. This safe and relatively varied diet should be the

backdrop against which you test staple foods.
The testing procedure changes over time, because your sensitivity may decline as the diet progresses.

During the first eight weeks, you should test one food each day, eating a normal-sized portion for

lunch or supper. A reaction to the food might occur quite soon after the meal, or some hours later. Any

symptoms that occur within the following 24 hours should be provisionally attributed to that food.
Unfortunately, bowel symptoms can sometimes take longer to develop – up to 48 hours. This can confuse

things when a new food is being tested every day.
There may also be uncertainty about intermittent conditions such as chronic urticaria. You may not be

absolutely sure that the problem really responded to the exclusion phase. If so, when the symptoms

recur during the testing phase, this may be due to a food, or it may just be coincidence.
Should there be any doubt about which food caused a particular set of symptoms, cut out all the suspect

foods for now, and retest them after a couple of weeks, using a three-day testing procedure (see

below).
When a reaction does occur to a food, stop all testing and go back to the safe diet until you feel

completely better. But don’t wait too long before resuming testing. You need to get through most of the

testing within eight weeks because, for some people, intolerance to the foods begins to fade after

that.
This does not mean that the intolerance has been ‘cured’, unfortunately. A period of eating the food

regularly will soon bring the problem back.
If you are still testing foods after eight weeks, you must change to three-day testing – eat a normal

portion of the food every day for three days, stopping only if you get symptoms. Should you have no

reaction to the food by the end of the fourth day, you can consider it safe. (But leave it out of your

diet for at least another four days.)
There are some special procedures for testing certain foods:
•    When you test wheat, even if it is quite early on, use the three-day test procedure (see

above). Reactions to wheat can be very slow. (If you have rheumatoid arthritis, you should spend a full

five days testing wheat, and eat it at least twice a day.) Don’t use bread to test wheat because this

also contains yeast and other ingredients. Use a pure wheat cereal such as Shredded Wheat – moisten it

with fruit juice if you cannot have milk. Note that some people who react to whole-wheat are sensitive

to the wheat germ, and can tolerate refined wheat, as in white bread and flour. For others only white

flour is a problem – they are usually reacting to additives in the white flour. Careful testing will

sort out these issues.
•    Test milk before cheese and butter. You may react to one but not the others. If you react to

fresh milk, wait a few weeks, then test evaporated milk. Later, you can test goat’s milk and then

sheep’s milk. Some people can tolerate these, but must be very careful not to consume too much of them.
•    You can test yeast using Marmite or yeast-based B-vitamin tablets. Do this before you test

mushrooms, •    At some point, test a canned food. This is to check for reactions to the lining

material used on cans. Choose something that contains no other ingredients or additives, such as

carrots. Test it first in a frozen or fresh form, so that you are sure you don’t have a reaction to the

food itself.
•    Throughout the testing period, continue with cooking all your own food from scratch. At a

fairly late stage in the testing, when you have tested most foods, spend three days eating packaged

food. The idea is to eat a wide range of different food additives all at once. Read the labels

carefully (see p. 172) to check that all the food ingredients are ones which you have already tested

and found safe. You are unlikely to react to these packaged foods, but if you do, you should then

conduct tests with all the individual food additives. You may need some help from a dietitian for this

(see p. 201).
Testing becomes more and more uncertain after 12 weeks. If you
have not completed it by then, reintroduce all the untested foods.
Should your symptoms come back, cut out all those foods again,
then test them individually.
What next?
For anyone who recovers during an elimination diet, and successfully identifies their problem foods, a

period of complete abstinence from those foods follows. After about a year, it is worth testing the

foods again, as the sensitivity may have subsided. (Don’t do this if you have rheumatoid arthritis –

see p. 23.)
If, after a year or two, you find that a food no longer makes you ill, don’t go back to your old ways –

remember that you must only eat the food occasionally. Once every three or four bays is a good rule of

thumb for a food to which you were previously intolerant. You might get away with having it slightly

more often than this, but never go back to eating it daily. If it starts to become your ‘favourite

food’ again – the thing you fancy more often than anything else – watch out.
Good nutrition is an important issue for anyone avoiding certain key foods. If you have cut out all

milk products, for example, you should probably be taking a calcium supplement, unless you eat a lot of

other calcium-rich foods. Ask your doctor to refer you to a dietician or nutritionist if you feel you

need help.
An elimination diet for children with eczema
Before putting your child on any kind of restrictive diet, it is vital that you talk to your doctor.

The risks of malnutrition are far higher for children, and there can be serious long-term consequences,

such as stunted growth or impaired intelligence. You must therefore have medical consent and

supervision for an elimination diet.
For young children with atopic eczema, there is rarely any need for a stringent elimination diet, such

as that described on pp. 194-7. Children are usually sensitised to only one or two commonly eaten

foods.
In the case of recently weaned infants, it is enough to simply cut out individual foods, one at a time.

Avoid each food for two weeks, while observing symptoms carefully.
For older children a simple elimination diet, with an exclusion phase which avoids just the most likely

culprits, works well. The foods that you should exclude at the outset are:
•    any food which has given a positive skin-prick test (see p. 69)
•    any food which you think may have caused digestive symptoms, such as diarrhoea, either now or

in the past
•    eggs, milk and all milk products
•    beef and chicken
•    citrus fruits (oranges, lemons etc.)
•    food additives.
If the child’s skin is no better after a week of this diet, cut out the following foods as well:
•    peanuts and other nuts
•    soya
•    fish
•    wheat and maize (corn)
•    tomatoes
•    lamb.
If there is no response after another week, food is unlikely to be contributing to the eczema.
For the testing phase, use three-day testing, as described on p. 197, if you have fewer than ten foods

to test. Use one-day testing if you have more than ten foods to test.
You should begin by testing a very small amount of the food. Wait ten minutes for any symptoms (not

just skin symptoms – the mouth or stomach may also be affected) then give a little more if nothing has

happened. Build up gradually to testing a normal portion of the food.
A more cautious approach is required for children who give positive skin-prick tests to foods, or have

a history of symptoms in the mouth or digestive tract. They are more likely to suffer severe symptoms

in the lips, mouth and throat – the type of reaction associated with food allergy. Emergency medical

treatment may be needed. You can see if there is any likelihood of a severe immediate reaction to foods

by starting with a test on the face, and then the outer lip (see box on p. 23). If nothing happens, it

is probably safe to go on to the next stage – giving the child a very small amount of the food to eat.

However, you should have medical supervision for Rare reactions
Very occasionally, atopic eczema sufferers on milk-avoidance diets develop a sensitivity reaction to

calcium supplements. There is no scientific explanation for this, but it has been very well documented

in two children. Should you encounter this problem, the answer may be some alternative natural source

of calcium: sardines or other small fish, eaten whole, are one possibility, assuming your child will

eat fish. A dietician can advise on how much is needed per day.
There has also been one well-documented report of a child reacting to mineral water. When the water she

usually drank was changed to another brand, her eczema cleared up. This is very unlikely to be a common

problem.
this procedure in the case of foods that gave positive skin tests. If your child has both severe eczema

and additional symptoms (such as nettle rash, or symptoms in the mouth or digestive tract) it may be

advisable to have medical supervision when testing all foods.
Bear in mind that atopic eczema naturally fluctuates a great deal. To observe the effects of trying out

a food, you need the child’s skin to be in a steady state. That means being absolutely consistent about

applying steroids and moisturisers, avoiding (for the period of testing) any stressful situations that

could provoke a flare-up, not exposing the skin to sudden doses of irritants or airborne allergens, and

keeping scratching under control. Be aware of other factors that could muddy the waters by provoking a

flare-up of eczema – such as teething, or a cold (see p. 44).
If certain foods are identified as provoking eczema symptoms, and you decide to cut the food from your

child’s diet, a nutritional supplement may well be needed. Ask your doctor to refer you to a

nutritionist or dietician.
Other diagnostic diets
These diets are not used by (or even known to) the majority of doctors. While some, such as the

low-nickel diet, have been subjected to rigorous scientific testing and have shown their worth, others

have not been tested scientifically. The evidence in favour of them is purely anecdotal – in other

words, doctors have used these treatments repeatedly and observed good results with some of their

patients. That is not hard science, but it is how innovations in medicine often begin.
There are few risks with any of these diets – the number of foods to be avoided is small, and you are

most unlikely to become malnourished. Your doctor should not object to you trying any of these diets,

however sceptical he or she may be about its possible benefits.
Low-nickel diet
This diet is sometimes of benefit to adults with eczema. There are various pointers which indicate that

the diet may help, as described on pp. 55-6.
Make sure that you have absolutely no contact with any nickel (e.g. in jewellery, jeans studs, watches

or hair clips) throughout this diet, and for at least two weeks before starting it.
Ideally you should also stop treatment with steroids or antihistamines a week or so before starting the

diet. This allows any improvement to be easily observed. Obviously you should get your doctor’s

permission to do this.
The diet could take anything from six weeks to six months to take full effect. Some people have a

complete clearance of their eczema, while for others there is a partial but distinct improvement.
The foods with a high nickel content, which should be avoided as far as possible, are:
•    shellfish
•    green beans and peas
•    beansprouts and lucerne sprouts
•    dry beans and lentils (pulses) of all kinds; soya protein and products containing it (e.g.

vegetarian sausages and burgers)
•    spinach and kale
•    lettuce, leeks
•    wheat bran (avoid bran cereals and other products; replace wholemeal bread with white bread, or

eat it in moderation only – you can get plenty of fibre from fruits and vegetables; do not eat

multi-grain breads at all)
•    oatmeal, millet and buckwheat
•    raspberries, prunes, pineapple, figs
•    chocolate and cocoa
•    tea from drinks dispensers (restrict intake of other tea and coffee, and don’t make them too

strong)
•    peanuts, hazelnuts, almonds and marzipan
•    liquorice
•    sunflower seeds, linseed
•    baking powder, in large amounts
•    vitamin or mineral preparations that contain nickel (check the label carefully), Nickel is also

found in drinking water, and absorbed from certain cooking utensils, so:
•    Do not use items plated with nickel (e.g. tea balls, some tea strainers, egg beaters). The

extremely shiny appearance of nickel makes these easy to recognise.
•    Do not cook acid fruits in stainless steel pans, since the acid leaches some nickel out of the

stainless steel. An enamel cooking pot is safe.
•    Minimise the amount of tinned food that you eat.
•    In the morning, run off the first litre of water from the tap, as this may contain nickel

released from the tap itself.
Several other foods and drinks seem to aggravate the skin of nickel-sensitive people, even though the

foods are not rich in nickel. These foods and drinks should also be avoided:
•    beer, wine
•    herring, mackerel, tuna
•tomatoes, carrots, onions, apples; oranges and other citrus fruits, including their juices.
Low-chromium and low-cobalt diets
Skin sensitivity to chromium or cobalt can, very occasionally, result in a tendency to react to these

same metals when consumed in food or drink (see pp. 56).
Unfortunately, both chromium and cobalt are essential for good nutrition, so avoiding them is fraught

with problems. You would need the help of a really good dietician, or a doctor with a particular

interest in nutritional problems, to guide you through a diet of this kind.
The only measure you can safely take at home is to cut down on excessive consumption of these metals,

for three weeks only, to see if this produces any improvement in your symptoms. If it does, that should

encourage you to seek expert help for a more thorough avoidance diet.
In the case of cobalt sensitivity avoid:
•    all canned and bottled beer.
In the case of chromium sensitivity avoid:
•    beer, wine and cider
•    yeast extract and yeast tablets
•    black pepper
•    calf’s liver
•    wheatgerm and wholemeal bread
•    cheese.
If you also have nickel sensitivity, avoid nickel-rich foods (see p. 199) at the same time.
Low-histamine diet
Histamine in food is mostly produced by bacterial action. The majority of people can break down any

histamine they eat, as long as the amount is not excessive (see box on p. 67).
Temporary susceptibility to histamine may accompany viral hepatitis or other liver conditions.
A permanently impaired ability to detoxify histamine is relatively unusual. When it does occur it can

result in symptoms such as chronic urticaria, migraine or recurrent headaches. A low-histamine diet may

help in these cases. All of the following should be avoided:
Very high histamine content:
•    red wine, champagne
•    tuna, sardines
•    Emmenthal and Camembert cheeses.
High histamine content:
•    beer, white wine
•    anchovies
•    Gouda, Roquefort, Stilton and all other well-matured cheeses
•    salami and other well-matured sausages, Westphalian ham
•    sauerkraut
•    spinach
•    tomato ketchup.
If you improve only partially on this diet, this may indicate that you are on the right track

(histamine is indeed the problem) but that the bacteria in your gut are undermining your efforts with

the additional histamine which they generate. You can investigate this possibility by trying a

low-carbohydrate diet, as described on p. 53.
Low-amine diet
Naturally occurring substances called amines, found in many different foods, can have a drug-like

effect on the blood vessels, making them open up a little and so increasing the blood flow. The effect

is usually small, but some people are more susceptible than others. A low-amine diet is worth trying if

you have chronic urticaria or migraines, and have not improved with other treatments. A low-amine diet

can also be useful in atopic eczema: amines in food are not a basic cause of eczema, but they can

aggravate the rash by increasing blood flow to the skin. To begin with, cut out all foods listed below:
Very high amine content:
•    all cheeses except cottage cheese
•    dark or plain chocolate
•    yeast extract (Marmite etc.), miso, tempeh, tomato paste, tandoori spice mix, stock cubes,

ready-made sauces •    cola drinks, orange juice, tomato juice
•    any dried, pickled or smoked fish
•    sausages, pies and smoked meats, beef liver, chicken skin
•    broad beans, spinach
•    sauerkraut
•    almonds.
High or moderate amine content:
•    milk chocolate
•    soy sauce
•    beer, wine and cider
•    pork, including bacon and ham, salami, chicken liver, offal
•    all fresh or tinned fish, except white fish
•    all nuts except chestnuts and cashews
•    sesame seeds, sunflower seeds
•    avocados, aubergines, mushrooms, tomatoes, broccoli, cauliflower
•    olives and olive oil
•    oranges, lemons and other citrus fruits
•    pineapples, bananas, raspberries, strawberries, pineapples, plums, grapes, dates, figs, kiwi

fruit, passion fruit.
Continue for at least three weeks, and longer if your symptoms are normally intermittent. if you

improve, you can then experiment with reintroducing small portions of foods from the second list, three

or four times a week. Gradually build up to a higher intake, but cut back if your symptoms return.
Organic diet
The objective here is to avoid pesticides, i.e. chemical sprays applied to kill fungi and insect pests.

This may be helpful for people with chemical intolerance (see p. 84).
`Chemical-free’ or ‘unsprayed’ food (crops grown without pesticides) will do just as well as 100%

organic food (which is grown without either pesticides or artificial fertilisers).
The highest intake of pesticides is from fresh fruit and vegetables, so if your budget is tight,

concentrate on buying organic or chemical-free versions of these. If you have a garden, growing some of

your own food will reduce the cost.
You can also reduce the pesticide content of ordinary fruits and vegetables by:
•    Storing them for as long as possible before using them, because the pesticides break down quite

quickly
•    Always peeling them. With difficult-to-peel items such as peaches and tomatoes, pour boiling

water over them and leave them to stand for a few minutes first, as this loosens the skin. Rinse in

cold water, then peel.
•    If peeling is not possible, washing them very well with soap or detergent, then rinsing them

thoroughly
•    Cooking them, as this drives off some of the pesticides; avoid inhaling the steam and ventilate

the kitchen well while doing this.
You should drink mineral water from a reputable source, or use a very high-quality water filter (not a

jug filter).
Additive-free diet
Food additives are occasionally the culprit in chronic urticaria (see p. 53). At the same time as

avoiding additives, people with chronic urticaria should cut out other potential culprits – alcohol,

spices and all aspirin-like drugs (see box on p. 151).
An additive-free diet may also be of value for some people with chemical intolerance (see p. 84).
In the case of children with Attention Deficit Disorder (ADD), also called Hyperkinetic Syndrome, the

role of additive-free diets is a contentious issue (see p. 81).
An additive-free diet is very healthy but quite hard work. It means making all your own food from 100%

fresh, unmodified produce (you cannot have bacon or ham, and even things like cooked chicken and

ready-to-eat salad can contain some additives; so does most restaurant food). Note that wines, beers

and other alcoholic drinks can contain many additives without declaring them on the label. (German

bottled beer is an exception here.) Baked goods sold unwrapped can also contain many additives without

declaring them.
Stop using toothpaste unless it is an additive-free brand. You can buy such toothpaste from a

health-food shop – or use sodium bicarbonate powder instead. Drink mineral water or filtered water (you

need a good-quality filter for this, not a jug filter).
Medicinal drugs can contain colourings and other additives, so you should try to get additive-free

versions. Talk to your pharmacist about this initially.
Assuming the symptoms clear up, testing can begin, but you will probably need medical help to work out

exactly which additives are at fault. It is difficult to organise these tests at home, because most

foods contain such a mixture of additives.
With chronic urticaria, there is the possibility of quite severe reactions on testing, so medical

supervision is desirable. You can undertake cautious testing with small amounts of tap water, spices

and alcohol at home, but make sure you are in a position to get emergency medical help if you need it.

Aspirin or aspirin-like drugs should not be tested at home. Life-threatening reactions are common in

sensitive individuals, and temporary avoidance can heighten your reaction.

Allergens: bees, wasps and other stinging insects

Saturday, May 23rd, 2009

Bees, wasps and other stinging insects

`Know your enemy’ is always a good motto, but particularly for those with insect-sting allergy. Being allergic to wasps or hornets, for example, is enough of a problem without panicking every time you encounter a hoverfly as well. If your reaction to this is ‘What’s a hoverfly?’ then you need a good field guide or a friend who knows a little about natural history. These common insects have yellow-and-black stripes to mimic those of wasps, giving them some protection against predatory birds. They fool a lot of people as well as birds, but it isn’t difficult to tell the two apart — hoverflies are a different shape from wasps, hold their wings differently at rest, and fly in a completely different way (for one thing they hover, unlike wasps). Being able to tell one from the other will make life much more relaxing.
If you did not see the insect that stung you, ask the doctor which skin tests came up positive (see p. 61), and use a field guide to check exactly what the insect(s) looks like.
As well as knowing what your problem insect looks like, you need to know a little about its habits and tastes.
These are the general characteristics of stinging insects that you need to know about:
• The most dangerous thing you can do is to disturb the nest – all stinging insects go into attack mode when this happens. If there is a nest in or around your house, call in a pest control expert to destroy it. Never tackle this job yourself, nor allow anyone else to do it while you are in the vicinity.
• If you think there may be an insect nest in or around your house, call in a pest control expert to do a survey. Regular annual checkups of your property are advisable if insects have nested before.
• Insect repellent works only for biting insects, such as mosquitoes. It does not repel wasps, bees or other stinging insects.
• Insecticide spray can be useful, but make sure the insect is really dead before you touch it. A groggy poisoned insect may well sting.
• A small but thick blanket can be useful for catching bees or wasps that have flown into cars. Don’t try to do this yourself unless there is no alternative. Ask a passer-by to help you if you are alone.
• Always stay as calm as possible.
Wasps and hornets (vespids)
• If you react to one species of vespid, you may well have a cross-reaction to other species in this group, so take care.
• Wasps like sweet foods (e.g. jam, honey, cakes) and you should avoid taking these on picnics. They will also crawl into open cans of beer or soft drinks. Never ever drink from the can, as you can get a mouthful of cross wasp with your drink.
• In spring and early summer, wasps collect protein-rich food for their young, and may be attracted to meat. If eating outdoors, as far as possible keep food covered.
• Wasps come to fallen fruit in the autumn. They get very sluggish and bad-tempered late in the year, and will sting with little provocation. They may crawl into crevices or hollow logs as winter approaches. Be very careful about picking up fruit or dead leaves, or working in the garden –always wear thick gloves.
• Wasps are often on the ground, especially in late summer and autumn. Wear shoes and socks for protection. If working outside where there may be wasps, long trousers and long-sleeved shirts are also advisable.
• Rubbish bins and litter bins are also very attractive to wasps. Make sure your own bin has a tightly fitting lid, and that no rubbish accumulates around it. Ask neighbours to do the same. Keep away from litter bins, and from picnic sites, orchards and tea gardens, all of which are havens for wasps.
Cross-reactions between insect stings
There are cross-reactions between the venoms of wasps, hornets and related insects (vespids), so if you are allergic to one, you may react to another. Cross-reactions are very unlikely between bee and wasp venoms.
Honeybees and bumblebees have very similar venom and these cross-react (but honeybee immunotherapy does not work for bumblebee allergy – see p. 168). Surprisingly, there is some cross-reaction between honeybee venom and snake venom.
The usual suspects
Wasps (yellow-jackets in the United States), hornets and bees are the most common source of allergic reactions worldwide. Locally, there are allergic reactions to various other stinging or biting animals. Fire ants are a particular problem in the southeastern United States. Hopper ants are a cause of anaphylaxis in Australia, and allergy to leech bites has been reported from Tasmania. A few people are allergic to the kissing bugs (Triatoma spp.) – also called cone-noses, ‘big bed bugs’ or ‘Mexican bed bugs’ – that are found in South and Central America, as well as rural areas of North America. These large insects creep into beds and bite painlessly, by night. In urban areas of Italy, where large numbers of pigeons live in some old buildings, pigeon ticks that find their way indoors have sometimes caused anaphylactic shock by biting during the night. Localised reactions to earlier bites had occurred in all cases.
Honeybees and bumblebees
• When it stings, a bee loses part of itself – the stinger and venom sac – and therefore dies. So stinging is very much a last resort. Most honeybees are not aggressive, and only sting if their nest is attacked, or if they are threatened when feeding.
• Bees feed on nectar from flowers. They may be attracted by brightly coloured clothes, especially red, orange and yellow, and flower-prints, mistaking these for flowers. Wearing dull colours is advised.
• Some perfumes, shampoos and scented cosmetics or lotions may also attract bees. If bees do approach you, never swat at them, and don’t panic. The best thing is to brush them away very gently.
• Bees often feed on clover, which grows in lawns and other grassy places, and it is easy to tread on them in this situation. Walking barefoot outside is therefore dangerous.
• Bees are attracted by water, including swimming pools and paddling pools.
• Although large, bumblebees are also very placid and rarely sting.
• Swarming bees are dangerous because they have the queen with them. If you see a swarm, keep well away.
Africanised honeybees
If travelling abroad, you should remember that Africanised honeybees – found in South and Central America, Texas, Arizona and parts of California – will sting with much less provocation than ordinary bees.
They are hybrids between domestic honeybees and an aggressive variety of wild African bee mistakenly introduced to South America. While they are much more pugnacious than ordinary bees, Africanised honeybees are only intent on defending their hive, and do not maliciously hunt people down as some horror movies have implied! They inject slightly less venom with each sting than a normal bee, but multiple stings are more likely because more than one bee is usually involved.

Allergies and Pregnancy

Thursday, May 21st, 2009

Allergies and Pregnancy
Great care is taken in prescribing drugs during pregnancy. This is something that doctors are now exceedingly cautious about, but do tell the doctor as soon as you decide to try for a baby. The foetus is most vulnerable to damage by drugs during the first three months, and especially the first few weeks after conception.
Your prescription will be changed if the drugs you are currently taking could pose any threat to the unborn child. A drug that has not had sufficiently rigorous testing for safety during pregnancy, or lacks a long track record, will probably be withdrawn. New drugs are generally considered to be slightly more risky than the tried-and-true older drugs: rare side effects may not come to light during the testing which precedes release of a drug, but they do become apparent once the drug is in widespread use for a long time (see pp. 136-7).
If you are already pregnant as you read this, don’t worry too much. With a few notable exceptions – certain antihistamines and antibiotics – most of the drugs used for allergic diseases do not pose any major risk to the unborn child. There is probably nothing to worry about, but see your doctor as soon as you can – and talk to a pharmacist, in the meantime, if you are concerned. Don’t panic, and don’t stop taking your drugs unless you are absolutely sure that you can do without them. Do not stop taking your drugs if you have asthma.
Some non-prescription medicines are best avoided during pregnancy. Read the packet carefully, and talk to your pharmacist if you have any doubts.
From the moment you start trying for a baby, remember to tell any medical personnel who treat you, and any pharmacist you buy medicines from, that you could be pregnant.
Immunotherapy and skin testing
Immunotherapy should not begin during pregnancy, because of the risk of anaphylaxis (see below), but pregnant women who are already undergoing immunotherapy can continue.
The safety procedures described on p. 166-7 should be followed with meticulous care.
Most doctors continue immunotherapy at a steady ‘maintenance dose’ because there is always a small risk of anaphylaxis with immunotherapy when the dose is increased. Some doctors are even more cautious and reduce the maintenance dose during pregnancy, but give more frequent injections – this minimises the chance of bad reactions.
Many doctors do not give skin tests for allergy during pregnancy, as these also carry a very small risk of anaphylaxis. If you do have skin tests, there must be resuscitation equipment available. Intradermal tests (see p. 92) are best avoided.
Severe allergic reactions (anaphylaxis)
Special care should be taken to avoid anaphylaxis during pregnancy as this may increase the chance of a miscarriage.
Injecting adrenaline during the first three months of pregnancy may carry some small risk of malformation of the baby. But the evidence here is uncertain, whereas the danger to your own life, if you don’t use adrenaline when you need it, is both certain and substantial. If you have an adrenaline self-injection kit, talk to your doctor now about what you should do in an emergency. The best policy is to be ultra-careful about avoiding your allergen, so that anaphylaxis does not happen.
Women who suffer from exercise-induced anaphylaxis (see p. 59) generally play safe by exercising less strenuously while pregnant. The problem can get worse during pregnancy, but it does not usually do so. Labour itself is very strenuous of course, but problems during the birth are uncommon. If anaphylaxis does occur, the reaction is usually quite mild – nettle rash only – and the baby is delivered alive and well. However, many women find that the attacks of exercise-induced anaphylaxis are more frequent and severe when they start exercising again after the baby is born. It is best to resume exercise very gradually.
Eczema and other skin problems
Atopic eczema may improve during pregnancy, probably because the body produces slightly more of its own natural steroid, hydrocortisone. Contact dermatitis may either improve or flare up.
Stretch marks often itch a great deal, and widespread itchy skin, with or without a rash, is a common problem during pregnancy. These are not usually allergic reactions, and no cause can be identified in most cases. The skin tends to recover a few days after the birth.
If there is itching in the vulva) area, this could be due to a Candida infection (your doctor can prescribe a safe treatment) or it might be just another of those unexplained itches of pregnancy.
Hayfever and other nasal allergies
The natural hormone changes of pregnancy affect the nose, which can become more blocked. If you have allergic rhinitis this will add to your woes. See your doctor and make sure that your drug treatment is adequate (see p. 29). The nose-clearing exercises on pp. 230-31 might also help.
Asthma
Severe asthma can be bad for both the pregnant mother and the unborn child. Uncontrolled asthma increases the risk of the baby being born prematurely – and premature babies are more likely to develop asthma themselves. The death rate for newborn babies is also higher if the mother has poorly controlled asthma.
Treating a severe asthma attack promptly helps to prevent any damage to the baby, so don’t hesitate to call an ambulance –and tell the operator you are pregnant. The ambulance should be carrying oxygen which is particularly important for helping the unborn baby through the attack.
If you have asthma, don’t stop using your drugs or reduce the dose unless advised to do so by a doctor. Because it is so important to keep asthma under control during pregnancy, your doctor may want to add, or increase, preventer drugs such as inhaled corticosteroids or sodium cromoglycate (see p. 148). It
also makes sense to monitor your peak flow twice a day (see p. 97) so that you have advance warning of serious attacks.
Unfortunately, some asthmatics – usually those who have severe asthma to begin with – get much worse during their pregnancy. In such cases, careful monitoring and increased use of preventer medicines are essential. The symptoms usually increase from week 24 to week 36 of the pregnancy. The last four weeks tend to be much better, and things are back to normal by about three months after the birth.
Some women with asthma have fewer symptoms while they are pregnant, and for others their asthma stays about the same.
Asthma can also appear for the first time during pregnancy, and may be quite severe. However, a relatively mild breathlessness can be due simply to the fact that, as the pregnancy advances, the chest cavity, and therefore the lungs, become compressed. This is not necessarily asthma.
This simple physical effect can also add to the difficulties experienced by women who were already asthmatic before they became pregnant.
GER (acid reflux) – see p. 38 – can contribute to asthma during pregnancy, and treating this problem may help.
Asthma attacks during the birth
Severe asthma attacks very rarely occur during labour, but it is still important that all the medical staff in attendance know you have asthma. They should also be told if you have taken steroid tablets during the previous two years. A record of when you took steroids, how long for, and at what dose, will be valuable. You may need a low dose of steroid to get you through the physical stress of labour (see p. 142). Some doctors believe that patients who have been using high-dose inhaled steroids should be treated in the same way.
Smoking
Smoking is a bad idea if you have allergies or any allergic tendency in the family. Smoking is a very bad idea indeed if you are pregnant, or a parent. This is the moment, if ever there was one, to give up.
Enlist your doctor’s help, and ask if counselling, psychotherapy or other forms of support are available. If you have tried all this before, and failed, then talk to your doctor about the possibility of using nicotine patches. Some doctors believe that, for pregnant women who smoke 20 cigarettes or more a day, the advantages of nicotine patches outweigh the risks to the foetus. Nicotine levels in the blood are lower with patches than with heavy smoking, and your baby is not enduring the hundreds of other toxins found in cigarette smoke.

Skin-prick tests as a method of detecting true allergic reactions

Thursday, May 21st, 2009

Skin-prick tests
This is an indirect method of detecting true allergic reactions. It is one of a family of skin tests that use a similar approach. The three different tests in this family are known as: skin-prick tests or prick tests, puncture tests, and scratch tests.
For the skin-prick test - the technique used in Britain - a small drop of liquid containing an allergen, such as grass pollen, is placed on the arm. The doctor makes a small prick in the skin, under the drop of liquid, allowing a minuscule amount of the allergen to get into the skin. A positive reaction is recorded if a red bump develops soon afterwards. For accuracy, the bump must be compared to positive and negative controls (see below).
The puncture method is very similar to the skin-prick test but uses a slightly different technique for breaking the skin. The term prick-puncture test covers both techniques.
With the scratch method, the skin is scratched lightly, and the allergen solution is then applied over the scratch. This method gives less consistent results than prick-puncture testing.
It is important to include a negative control in the test - a skin-prick test with plain salt water (saline). This should not produce much of a bump - if it does, the skin is clearly over-reactive and the tests more difficult to assess. The doctor should also include a positive control - a skin-prick test with histamine, the substance that plays a central role in allergic reactions. This should always produce a bump. If it does not, the skin is decidedly under-reactive, and the tests are invalid.
Taking antihistamines will make the skin under-reactive, and you should stop taking them before the testing, for a period ranging from a day to several weeks - it varies depending on the particular antihistamine. Ask your doctor for specific instructions about stopping these and other drugs before testing.
Skin tends to be over-reactive to testing in people with dermatographism (see p. 52). Blood tests for specific IgE,
such as RASTs (see p. 92), are needed for anyone who has this condition. Eczema sufferers with a rash over large areas of the body may also require blood tests, if there is too little clear skin for testing.
Skin-prick tests can produce both false positives and false negatives (see box below). Some allergic diseases will give a lot of false negatives and relatively few false positives, while for others the reverse is true. The allergen itself influences the rates of misleading reactions: for example, tests for soya allergy are notoriously unreliable, whereas those for peanut are far more accurate. The age of the person being tested also makes a difference. With all these influences at work, interpreting the test responses is a real art, and the doctor’s experience counts for a lot.
All sorts of people offer skin-prick tests, including alternative practitioners. Get them done by a qualified doctor, preferably by an allergist, who will know how to make sense of the reactions.
Note that the purpose of these tests, and of blood tests for specific IgE, is to identify the allergens that are bringing on your symptoms, not to predict how strongly you will react to those allergens. The tests may give some indication of the intensity of your reaction, but they cannot be regarded as a good guide to how you will respond to the allergen in the future.
The safety record of skin-prick tests is very good. Occasionally a systemic reaction (anaphylaxis) occurs with these tests, but there are no records of any deaths. Nevertheless, if you suffer from severe asthma or have experienced anaphylactic shock in the past, it is advisable for the doctor to have adrenaline and resuscitation equipment available. Those with strong allergic reactions to latex may also react badly if they are tested with an allergen that cross-reacts with latex (e.g. cypress pollen), not just when tested with latex itself. Taking beta-Mockers (see box on p. 150) increases the risk of a life-threatening reaction for anyone in these higher-risk categories.
False positives and false negatives
Apart from challenge tests, none of the tests used for allergy works with 100% accuracy. Most give both false positives and false negatives.
A false positive means that there is a positive test but no actual reaction when the allergen is encountered (e.g. eaten or inhaled). A false negative means that there is a negative test result despite a genuine reaction (as shown by a challenge test, for example).
A test that gives relatively few false positives has good positive predictive value - in other words, if it suggests you are allergic to something, you probably are.
A test that gives relatively few false negatives has good negative predictive value. If it comes up negative, you are probably not allergic to that allergen.
Some tests for allergic reactions show good positive predictive value but poor negative predictive value, while for other tests the reverse is true.
Fresh is best
The fruit and vegetable allergens that provoke Oral Allergy Syndrome (see p. 63) are chemically unstable, so commercially produced extracts for skin-prick testing quickly lose their potency and give false-negative results. Most allergists now favour using a drop of fresh juice from the fruit or vegetable concerned.
Intradermal tests
These tests (also called ‘intracutaneous tests’) put allergen more deeply into the skin than prick-puncture tests. The skin tends to react more when penetrated to this depth, so there are more false positives. There is also a greater risk of a serious reaction which may require emergency resuscitation. Don’t undergo these tests if you are taking beta-Mockers (see box on p. 150).
Blood tests for IgE
There are blood tests that look at the total amount of IgE (the allergy antibody), which is sometimes useful in diagnosis. But more important are blood tests for specific IgE – against egg or grass pollen or latex, for example. There are different ways of measuring the IgE in the blood, the most commonly used being a radio-allergosorbent test or RAST.
Research shows that RASTs are no more accurate than skin-prick tests in confirming real-life allergic reactions. However, they are useful for patients who can’t discontinue their antihistamines without developing severe symptoms, and for those with dermatographism or very severe eczema (see p. 91).
Patch tests
These tests, used primarily for contact dermatitis, are similar to straightforward challenge tests, because the suspect substances are applied directly to the skin.
The test substances are placed on the skin – usually on your back – in small chambers. They are held in place with sticky tape, and left there for several days. Ideally, the reaction of the skin should be checked three times: after two days, again the next day, and again the day after that. It really is worth going back for all these separate visits, because the accuracy of the test increases greatly with repeated checking.
The substances chosen for testing are a standard set of antigens that most commonly cause contact dermatitis. This standard set will pick up 60-80% of all sensitivity reactions in contact dermatitis. If you have substances that you suspect may be causing symptoms, such as cosmetics, the doctor can usually test for these too.
You should not be tested while you still have a rash, as the testing will probably make the existing rash flare up, even though the test patches are applied well away from the rash.
Use of steroid creams and any light treatments (including exposure of the test area to ordinary sunlight) must stop at least a week before testing starts, or the results will not be accurate.
Interpreting patch tests requires a huge amount of skill, plus extensive knowledge of the finicky details of the different test substances. You need a dermatologist with considerable experience in this area.
False positives (see box on p. 91) can occur, especially if you react very strongly to one of the substances tested – some people develop what dermatologists call an ‘angry back’, and this generates false positives to various other substances being tested at the same time. Should you be told that you are sensitive to a great many different things, you may want to query this reading of the test. Ernest N. Charlesworth, an allergist and dermatologist at the University of Texas, describes patients who ‘develop into environmental cripples’ after being told that they are definitely sensitive to multiple antigens, on the basis of misinterpreted false-positive patch tests.
False negatives (see box on p. 91) are also possible, even with very careful testing. Should this occur, a type of challenge test known as a ROAT (Repeat Open Application Test) is possible. The suspect substance is applied to the inner fold of the elbow twice a day for a week. Get your doctor’s agreement before trying this test.
Endoscopy and biopsy
Miniaturised cameras and sophisticated fibre-optics have allowed modern doctors to do something that their predecessors could never have imagined possible – look right inside the human body. This procedure is called endoscopy, and it has a useful role in a few sensitivity reactions.
Looking inside the sinus cavities can assist in understanding exactly what is going wrong in chronic sinusitis. Inspecting the digestive tract can be valuable in several of the non-IgE immune reactions to food, such as coeliac disease (see p. 70) and eosinophilic gastroenteritis (see p. 72).
A biopsy is often carried out at the same time as endoscopy.
s involves taking a small sample from the affected area, such as
I ning of the gut, and studying it in detail under a microscope.
One purpose of a gut biopsy is to look for characteristic :goes of damage to the lining of the gut – such as the distinctive charges produced by untreated coeliac disease. A biopsy can also reveal what kind of immune cells are present. Abnormal numbers of certain immune cells, for example, eosinophils (see p 19), may suggest a particular diagnosis.
Another way of looking at what kind of immune reactions are going on, used for lung diseases, is a bronchoalveolar lavage – iterally a ‘washing out’ of the airways and lungs, allowing immune cells to be collected and studied. This diagnostic technique is lased for Heiner’s Syndrome (see p. 72).
Tests for food intolerance
The only really effective way of testing for food intolerance is an el ruination diet (see pp. 194-7). This is the gold standard. However, it is neither easy nor quick – which has led to a constant search for alternative tests.
The proposed alternatives are all indirect tests, that is to say, non-dietary. The results of the tests are used as a basis for an avoidance diet. In other words, the foods that give a positive test result are avoided.
Some of these tests use samples of hair or blood, others use pulse testing, pendulums, or muscle strength tests (’applied kinesiology’). A few of these tests do show some promise. Pulse tests, and a blood test called the ‘lymphocyte transformation test’. for example, can give a general indication of sensitivity reactions – sometimes. However, even in the most expert hands, these do not give a result that is accurate enough to be useful.
Of the other tests that are available, most have not been evaluated at all objectively.
Many of them are advertised directly to the public, and one of the problems with this approach is that the testing company starts by assuming that food is the problem. The same is usually true of ‘dietary therapists’ and others in the alternative health field offering tests of this kind.
Almost everyone who undertakes such tests is given a fairly long list of foods which have come up positive in the tests. This does not fit with the evidence from medical trials in which a group of people with irritable bowel or migraine (typical food intolerance symptoms) undertake an elimination diet. A significant proportion of them always find that they do not have food intolerance. Of the rest. many find that they react to one or two foods only. The long lists of foods produced by the commercial tests are, to put it mildly, implausible.
With tests that require a sample of blood, sending off two blood samples from the same person, under different names, is a simple way of assessing the tests’ validity. This exercise has been tried several times with different testing companies, and every time two completely different lists of foods have been sent back.
Covert studies of this kind have also shown that the tests overlook genuine reactions. In one alarming case, a woman with a true allergy to peanuts was assured by a ‘dietary therapist’ that she really could eat peanuts safely.
Many people with food intolerance will tell you that they did well after following a diet based on such tests – and they may well have done. Given that common foods such as wheat and milk are regular offenders in food intolerance, and that these foods very frequently feature on the lists of positive test results generated by commercial testing companies, quite a few people should do well. The problem is that these people may also be avoiding many other foods quite unnecessarily.
Furthermore, if people have sensitivities to some other foods that are not on the list, they will be missing out. They could enjoy a far better level of health if all the foods causing symptoms were Identified and removed from their diet.
In the end, an elimination diet is both cheaper and far more likely to give the right answers.
Testing for IgG antibodies
In diagnosing food intolerance, a few doctors offer tests for a type of antibody called IgG. This antibody is formed to any food molecules that get Into the bloodstream after a meal – and some do, even in entirely healthy people. So finding IgG antibodies to food molecules is not indicative of any disease at all. It occurs in everyone and is perfectly normal.
Nevertheless, some doctors feel that by measuring the level of IgG antibodies to foods, they can get a general idea of the permeability of the gut wall (which might possibly be true) and of particular foods that could be causing intolerance reactions (very doubtful – the tests just tell you what you eat most, and you know that already).
This test does measure something real, unlike some of the alternative tests for food intolerance. But the relevance of what it measures to the health of the individual concerned is partial and indefinite. A recent study of IgG testing for irritable bowel syndrome has confirmed this view.
In short, blood tests for IgG antibodies to food molecules seem like very poor value for money, and potentially misleading, whereas an elimination diet is a far more precise way of pinpointing food intolerances.

FOOD SENSITIVITY IN ASTHMA, ECZEMA AND OTHER ALLERGIC DISEASES

Monday, May 18th, 2009

FOOD SENSITIVITY IN ASTHMA, ECZEMA AND OTHER ALLERGIC DISEASES
In 1995, medical researchers in North Carolina, USA, asked over a hundred dermatologists how they treated atopic eczema. All used standard treatments such as moisturisers and steroid creams, but only 14% mentioned the possible role of food to the parents of children with eczema.
Between them, the dermatologists in this study treated about 17,000 children with atopic eczema per year. Using the most widely accepted estimates for food sensitivity in atopic eczema –38% of eczematous children are sensitive to food – one can calculate that there were over 5000 children in this study area who might perhaps have benefited from avoiding a problem food, but whose parents were never told about this treatment option.
North Carolina is by no means unique. The situation is much the same in other parts of the world, which adds up to millions of children and parents not even being told about a treatment that is frequently effective.
Other allergic diseases (see right) can also be triggered by food, although the percentage of patients affected is much lower than for atopic eczema. Here too, many doctors are unaware of (or sceptical about) the possible role of food.
These reactions are best described as ‘food sensitivity’. They cannot be called food allergy (see p. 62) if there are no symptoms in the mouth or gut and if skin-prick tests are negative – as is often the case. Negative skin tests suggest that the reaction is not IgEmediated (see box on p. 12).
However, in some children with atopic eczema. the skin-prick tests to culprit foods are positive. When these foods are eaten after a period of avoidance, such children sometimes suffer an
immediate reaction, with symptoms typical of true food allergy. For these individuals, their atopic eczema seems to be a symptom of IgE-mediated food allergy.
How can an atopic eczema reaction in response to food be IgE-mediated in one individual and not in another? Research is finally beginning to answer this question (see pp. 18-19).
The allergic conditions that may sometimes be induced, or simply aggravated, by a non-immediate reaction to food are:
• atopic eczema (atopic dermatitis)
• asthma
• perennial allergic rhinitis (constantly blocked or runny nose)
• chronic sinusitis
• secretory otitis media (’glue ear’).
In all of these conditions, many other causes exist. Except in the case of eczema, the other causes are far more likely than sensitivity to food. This fact will weigh heavily with your doctor, whose instinct, quite sensibly, is to look for likely causes first.
Taking asthma as an example, food sensitivity is relatively unusual as a primary cause, whereas allergy to airborne items. such as pollen or house-dust mite, is very common. Food probably affects only 8-10% of asthmatics overall, but is much more important for those with brittle asthma (the most severe and unstable form), affecting as many as 60% in a recent study.
The pollen connection
People who suffer from both birch-pollen allergy and atopic eczema may have worsening eczema when they eat certain fruits and vegetables, e.g. apples and carrots. These same foods cause Oral Allergy Syndrome (see box on p. 63) in some with birch-pollen hayfever, but they can aggravate eczema without causing Oral Allergy Syndrome.
Diagnosis
Consider other likely allergens first. Look at p. 28 for the airborne allergens that could play a part in perennial allergic rhinitis, chronic sinusitis, secretory otitis media (’glue ear’), and asthma. Only in the case of children with atopic eczema is food a prime suspect (between 38% and 69% of children with atopic eczema are affected by food), but even here there are a lot of other factors to consider (see pp. 43-4).
If you do decide to investigate the role of food, don’t abandon basic treatments in the meantime. By neglecting these. you could make the whole problem a great deal worse.
There are various clues that food is at fault:
• If you have other symptoms that suggest food intolerance (see p. 76). These problems often seem to go together with food-induced asthma or rhinitis.
• If you have noticed that a particular food makes your symptoms worse. Where there is intolerance to one food, there could well be intolerance to another, which you have not noticed.
• If you have exercise-induced asthma (see p. 41) and sometimes respond severely to exercise but sometimes have little or no reaction. Sensitivity to a food or foods may be instrumental in changing the response to exercise.
• If you have brittle asthma – but you must get your doctor’s consent for an elimination diet. Foods must be tested under medical supervision as severe life- threatening asthmatic reactions can occur on testing.
• If there are also digestive problems such as diarrhoea, vomiting or belching. This is a strong clue in the case of children with atopic eczema. Symptoms such as diarrhoea frequently precede atopic eczema, and it seems likely that a reaction to food in the gut increases the leakiness of the gut wall, allowing more food molecules through to the blood.
• If there is pronounced eczema around the mouth in children (but this can also be due to constant licking),
• For adults with atopic eczema, if there is a persistent rash on the hands, or the lips. Where there is a blistering rash on the hands that erupts at regular intervals, food is often the problem – or it may be metal contaminants of food such as nickel (see pp. 55-6). In general, food sensitivity is rarer among adults with atopic eczema than it is among children.
Skin-prick tests (see p. 91) for commonly eaten foods are worth
trying in all the diseases – if they give a positive result, they should
be noted, but if they give a negative one, they should be disre-
garded. The many alternative tests being marketed (see p. 93) are
highly inaccurate and unlikely to help.
Research from Tampere University Hospital in Finland suggests that babies are much more likely to give false-negative skin-prick tests for food than older children and adults with atopic eczema. The Finnish researchers found that 52% of babies with atopic eczema give a negative skin-prick test despite having a genuine reaction when tested by food challenge. In an attempt to tackle this problem, they have devised a patch test, similar to those used for contact dermatitis. The patch test, in which food is applied to intact skin and left there for two days, gives false negatives in only 39% of babies.
The best way to detect food-sensitive eczema, according to Dr Erika Isolauri. who heads the Finnish research team, is to use both tests, and take note of a positive reaction to either. This detects 80-90% of eczema-causing food reactions in infants.
Few other doctors are currently using patch tests for atopic eczema; because so much controversy surrounds this topic, and no standardised method has yet been devised. You may be lucky and find a specialist who does these tests.
To confirm the role of particular foods in atopic eczema, a food challenge test is essential, having first avoided the food carefully for two weeks. Great care is needed in testing (see p. 198).
If you cannot get suitable tests done. a simple elimination diet will be needed (see p. 198).
Treatment
There is a choice here, between avoiding the offending food, or eating normally and controlling the symptoms with drugs.
The difficulty comes when parents have to make this decision on behalf of their children. Unfortunately, there is insufficient evidence as regards the consequences of this decision. Treating food sensitivity can reduce the eczema symptoms substantially in the short term, but it does not necessarily improve the long-term prospects for the child. Orthodox doctors tend to think that eating a normal diet is much better for a child nutritionally and socially, and they have a point.
Doctors with a special interest in food sensitivity generally believe that treating the problem at source, rather than just suppressing the symptoms with drugs, must take the pressure off the child’s immune system, and give the child a better chance of growing out of sensitivity reactions in the long run.
The decision is yours – but it is vital that the diet is not more of an encumbrance than the disease itself, and that the child’s interests come first (see pp. 170-71). Whatever you do, don’t allow a child to become malnourished (see p. 198).