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Posts Tagged ‘sensitivity reaction’

Principal Drugs A-Z (dimethicone - dopamine)

Friday, June 26th, 2009

dimethicone Activated dimethicone is an antifoaming agent, said to reduce flatulence and protect mucous
membranes. It is a constituent of many antacid preparations. It is also present in some water-repellent skin creams.
dipipanana A rapidly acting morphine-like analgesic of value in the sever rain 4 to -1 dk–
Dose: 30-3450 mg (fail),, but it is usually• given in association with cyclizine as Diconal. The side-effects are similar to those of morphine.
dipivefrine A pro-drug that is converted into adrenaline after absorption. It is used
in chronic open angled- glaucoma as eye
drops (0.1%). (Propine). See page 138 and Table 16.
dimethylsulphoxide (DMSO) An organic liquid, it has been used for the symptomatic relief of interstitial cystitis
(Hunner’s ulcer) by the bladder instillation of 50 ml of a 50% solution. (Rimso-50).
dinoprost Prostaglandin F,.. It has actions and uses similar to dinoprostone.
(Prostin 112).
dinoprostone A synthetic form of prostaglandin E,. It has been used to initiate contractions of the pregnant uterus. Dose: 500 pg orally to induce labour, repeated if necessary at hourly intervals; as vaginal tablets or gel, 3 mg. Side-effects are nausea, diarrhoea, shivering and dizziness. (Prostin E2; Prepidil).
dioctyl sodium sulphosuccinate See dOCUSalC.
diodone injection A solution of a complex organic iodine compound, used as a contrast agent in X-ray examination of kidneys and ureters.
diphenhydramine One of the early antihistamines, with a more sedative action, and use(] in the temporary relief of insomnia. Dose: 10-25 trig. (Medinex. Nytol). It is also present in some cough preparations and nasal decongestants.
diphenoxylate A derivative that resembles codeine III reducing intestinal activity. It is used for the symptomatic relief of diarrhoea, and is usually given with a small dose of atropine to discourage excessive dosage and to reduce the risk of dependence. Dose: 10 mg initially, then 5 nig every 6 hours as required. (Lomotil;’Fropergen).
diphenylpyraline An antihistamine used as .I decongestant in colds and sinusitis. Present in Eskornadc.
dipyridamole An inhibitor of thrombus formation by reducing the adhesiveness of blood platelets in the arterial circulation. Dose: 300-600 mg daily before food. s I
ide-effects include nausea, diarrhoea and headache. (Persantill).
disodium cromoglycate See sodium cromoglycatc.
disodium etidronate See etidronate. disodium pamidronate See pamidronate.
disopyramide A quinidine-like drug used in the treatment of cardiac arrhythmias especially after myocardial infarction. Dose: 300-800 mg daily; dose by slow i.v. injection under ECG cover, 2 nig/kg up to 150 mg, followed by oral therapy as soon as possible. By its anticholinergic action care is necessary in glaucoma and prostatic enlargement. Contraindicated in heart block. (Dirythmin; Rythmodan). See page 1;6 and “fable 24.
distigmine An inhibitor of cholinesterase similar to neostigmine but with a longer action.
Dose: in the control of myasthenia gravis 5-20 mg as a single morning dose before breakfast; in urinary retention after surgery, 5 trig daily. It is sometimes used in neurogenic bladder disorders. Side-effects are nausea, abdominal cramp, diarrhoea and weakness. (Ubretid).
disulfiram When taken with even small amounts of alcohol, disulfiram permits the accumulation of acetaldehyde in the body, with side-effects such a flushing, giddiness, vomiting and headache that may be severe. Distilfiram is used in chronic alcoholism, but prolonged treatment and co-operation of the patient are essential.

Dose: after at least 24 alcohol free hours: 800 nig on the first day, falling over 5 days to 100-200 mg daily. Acute confusion may occur if given at the same time as tucLro-
llidazole. (Antabuse).
dithranol Synthetic compound used locally in the treatment of psoriasis. It is a powerful irritant, and treatment should be commenced with a simple ointment or zinc paste containing 0.1% ofdithranol, gradually increased to 1% if well tolerated. Higher concentrations are sometimes used in ’short -contact -time’ therapy.
Dose: 100 mg/m’ by i.v. infusion over
I hour. Rapid and severe hypersensitivity reactions (hypotension, bronchospasm) may occur, and treatment must be irrnediat4y available. Reaction risks may be reduced by premedication with jexalnetha&one given the day before treatment and continued for 5 days. Rash, pruritus and neutropenia may occur, and blood counts and liver function tests are necessary. (Taxotere). See page 122 and Table 8.
docusate A surface-active agent used as a faeces -softening laxative.
Dose: ill, to 500 nig daily. (Dioctyl).
diuretics The most widely used group of diuretics is the thiazides, represented by bendrofluazide (see page 14I ). They act mainly by increasing the excretion of
sodium by inhibiting its re-absorption by the distal tubule of the kidney, and evoke a rapid response which may persist over 12-24 hours, although some, such as chlorthalidone, have a still longer action. They are given in mild cardiac failure, oedema and in hypertension, but in more severe conditions, and in pulmonary occlema, the more powerful ‘loop’ diuretics, such as frusemide, which act at a different point, are preferred. A side-effect of some thiazides is an increase in the excretion of potassium which may require the use of potassium supplements or a change to a potassium sparing diuretic such as trianiterene. Spironolactone, an aldosterone antagonist, is a more powerful diuretic, of value in resistant oedema. Osmotic diuretics such as mannitol are used mainly in cerebral oedema. Simple diuretics such as potas slum citrate arc mainly used to alkalize the urine and promote diuresis in cystitis and similar conditions. See page 141 and Table 18.
dobutamine A sympathomimetic agent similar to isoprenaline, but with a more selective stimulant action on the beta, receptors in the heart. It increases cardiac contractility but is less likely to cause tachycardia. Useful in acute heart failure and cardiogenic and septic shock. Dose: 2.5-5 pg/kg/min by i.v, infusion, carefully adjusted to need. (Dobutr= Posiject). See page 141 and Table 18.
docetaxel A potent cytotoxic agent derived from the Pacific Yew. Used in advanced breast cancer resistant to other therapy.
domperidone An antiemetic that functions as a dopamine antagonist, as it prevents dopamine from reaching the receptors in the chemoreceptor trigger zone (see antiemetics). It is mainly of value in the severe nausea and vomiting caused by cytotoxic drugs, and is also useful in fum clonal dyspepsia. It is of little value in postoperative and travel sickness.
Dose: 10-20 mg 4-8-hourly; 30-60 nig by suppository. Sedative side-effects are infrequent, as domperidone does not cross the blood-brain barrier. (Motilium). See page 77.
donepezil A reversible inhibitor of anti-cholinesterase. Alzheimer’s disease is linked with a deficiency of acetylcholine in the brain, and donepezil may relieve sonic of the symptoms of that disease by increasing brain acetylcholine.
Dose: 5-10 mg at night. Diarrhoea and muscle cramps are side-effects. (Aricept ).
dopamine A sympathomimetic agent with actions and uses similar to dobutamine. Dose: 2.5-10 pg/kg/min by slow i.v. infusion. Careful control ofdose is essential, as dopamine may cause vasoconstriction with higher doses and increase the risk of heart failure. (Intropin). Dopamine is also a central neurotransinifter, and a deficiency is associated with parkinsonism. See levodopa, page 141 and “table 18.
dopexamine A short-acting drug of the dopamine type but with a more powerful action on the 0,-receptors. It is used in heart failure during cardiac surgery.

Principal Drugs A-Z (dextromoramide - dimenhydrinate)

Wednesday, June 24th, 2009

dextromoramide A powerful synthetic analgesic with a shorter and less sedating action than morphine. Of value in severe and intractable pain, and in terminal disease.
Dose: 5 ing or more either orally or by injection, according to need and response. Care is necessary in liver dysfunction and respiratory depression. (Palfitunt).
dextropropoxyphene An orally effective analgesic. Of value in many painful conditions, and in malignant disease its use may delay the need to resort to the opiate analgesics.
Dose: 250 ing or more daily, but doses in excess of 700 mg daily may cause toxic psychoses and convulsions. (Doloxene). See co-proxaniol.
dextrose See glucose.
diazoxide An inhibitor of insulin secretion. Dose: given orally in doses of 5 ing/kg or more daily in severe hypoglycaemia. Also of value in severe hypertensive crisis, in
doses up to 150 mg by rapid i.v. injection. Side-effects arc nausea, tachycardia and oedema. (Eudernine).
diclofenac A non-steroidal anti-inflammatory drug (NSAID) of the naproxen type, pe, and used in rheumatoid, arthritic and similar conditions.
Dose: 75-150 ing daily, after food. Suppositories of 100 nigare useful at night, but may cause local irritation. In acute conditions and in postoperative pain, doses of 75 mg once or twice a day by deep i.m. injection for not more than 2 days. (Diclomax; Voltarol). Like other NSAIDs, diclofenac may cause gastric disturbance and hypersensitivity reactions. See page 165 and Table 29.
diamorphine A derivative of morphine with a more powerful analgesic an(] cough-suppressant action. It is also less liable to cause nausea. Valuable for the relief of severe pain and the suppression of useless cough. Addiction is a constant risk owing to the euphoric effects of the drug.
Dose: 5-10 nig orally or by injection, repeated as required. For severe pain in the terminally ill, addiction is of no consequence, and much larger doses are given according to need: if necessary, by continuous infusion or a syringe-pump device.
diazepam A benzodiazepine of value in anxiety states, insomnia, acute alcoholic withdrawal, and for premedication. It also has a muscle relaxant action, and is valuable when given by injection in status epilepticus and in the control of the spasm of tetanus.
Doses: 5-30 mg daily, 10-20 mg by slow i.v. injection as required, up to a maximum of 3 mg1kg in 24 hours. Absorption after Lin. injection is unreliable. It is sometimes given as suppositories of 5-10 ing. Side-effects are drowsiness, dizziness, respiratory depression and hypersensitivity reactions. Care is IICLL’N nary in glaucoma and renal and hepatic impairment. Fxterided treatment may lead to dependence and addiction, and withdrawal should be slow to avoid the risks of precipitating toxic psychosis, confusion and convulsions. (Stesolid; Valium). See pages 177 & 136, an(] Tables 5 & 15.
dicobalt edetate A specific antidote in acute cyanide poisoning; toxic in other conditions.
Dose: 300 mg by slow i.v. injection, followed by 50 ml of glucose solution 50%, repeated if required. (Kelocyanor). Sec .odium nitrite.
dicyclomine An anticholinergic agent used to reduce gastric hyperacidity and the smooth muscle spasm of gastrointestinal disorders.
Dose: 30-60 mg daily. Side-effects
include dryness of the mouth and blurred vision. (Ivlcrbcnlyl).
didanosine An antiviral agent used in HIV infections not responding to zidovudine. Dose: 400 mg daily before food. Diarrhoea, vomiting and peripheral neuropathy are side-effects. (Videx contains didanosine with antacids). See page 144 and Table 19.
dienoes A synthetic oestrogen used as a 0.025% cream for senile or atrophic vaginitis.
diethylcarbamazine A synthetic drug used in filariasis but long-term treatment is necessary.
Dose: I mg/kg daily initially, slowly increased to 6 mg/kg daily, and continued for 21 days. Low initial doses are necessary to reduce allergic reactions due to proteins released front dead %vornis. Side-effects include headache, nausea, rash and conjunctivitis. (I letrazan). See ivermectin.

diflucortolone A corticosteroid used topically as a 0.13′0 or 0.3% cream or ointment in steroid-responsive dermatoses. Of value in resistant conditions. (Nerisone).
diflunisal An anti-inflammatory and analgesic drug (NSAID), chemically related to aspirin, but with actions and uses similar to napmxen.
Dose: 500 ilig– I g daily. Care is necessary in aspirin-sensitive patients, and in peptic ulcer. (Dolobid). See page 163 and Table 29.
Digibind A highly purified preparation of sheep-derived digoxin-specific antibodies, given by i.v. infusion in digoxin overdose or poisoning. It mobilizes digoxin from cardiac receptor sites and binds it as an inert complex which is excreted into the urine, and symptoms of digoxin toxicity subside within an hour.
Dose: depends oil the amount of digoxin absorbed; 40nigcan neutralize about 600ligofdigoxiii.
I Dim
250-500 jig initially according to need. Nausea and vomiting are often signs of overdose. If the heart rate falls below 60 beats per minute, dosage rcquiresadill.ltmclit. See page 1.11 and Table 18.
digoxin- specific antibody See Digibind.
dihydrocodeine An analgesic derived from codeine, but with a more powerful action. Of value in many painful conditions where mild analgesics are inadequate. Dose: 30 mg orally after food, or 50 ing
by i.m. or deep s.c. injection at intervals of 4-6 hours according to need. Dizziness and constipation are side-effects. MIA 18).
dihydrotachysterol A sterol related to calciterol, but with more rapid calcium-mobilizing properties. It is used mainly in hypocalcaemia and parathyroid tetany, but is sometimes effective in calciferolresistant rickets.
Dose: 200 jig daily, adjusted to need according to plasma calcium levels as a solution in oil. (AT 10).
39
digitalis The dried leaf of the foxglove. It has a powerful strengthening and regulatory action oil the heart, but is now used as digoxin.
digitoxin The most powerful cardiac glycoside of digitalis and of value in heart failure and atrial fibrillation. Absorption is rapid but excretion, which depends on metabolism by the liver, is very slow, and cumulative effects may occur.
Dose: (maintanence) requires careful .iditminent, varying from 50-200 f.ig daily.
digoxin The principal cardiac glycoside obtained from digitalis leaf. It is rapidly absorbed orally, and is widely used in cardiac failure, paroxysmal tachycardia and atrial fibrillation. The diuresis of digoxin therapy is a secondary effect following on the improvement in the renal circulation.
Dose: for rapid digitalization, 1-1.5 mg initially over 24 hours: subsequent maintenance close 62.5-500 pg daily. For slow digitalization, 250-500 pg may be given daily for about a week, with subsequent closes based on the response. Elderly patients and children respond adequately to smaller doses, and tablets of 62.5 pg (Lanoxin-111G) are available for such patients. In emergency, digoxin call be given by slow i.v. injection in closes of
diloxanide A well-tolerated aniciellicide used in chronic intestinal anicielliasis when only cysts are present in the faeces. It is also used in acute infections, 5 days after a course of metronidazole.
Dose: 1.5 g daily for 10 days. (Furamide).
diltiazem A calcium channel blocking agent, used in the prophylaxis and treatment of angina, and useful when beta-blocking agents are unsuitable or ineffective.
Dose: 180-360 nig daily, reduced in renal impairment. It may cause bradycardia, ankle oedema and hypotension. potension. (Adizen; Tildiern). Sonic long-acting products with various brand mantes are used in hypertension. They should not be regarded as interchangeable, as the duration of action may vary. See page 114 and Table 4.
dimenhydrinate An antihistamine used mainly as all antiemetic in nausea, travel sickness and vertigo.
Dose: 100-300 ing daily. It may cause more drowsiness than sonic related drugs. (Dramamine).
dimercaprol (SAL) A specific drug for the treatment of poisoning by arsenic, mercury, gold and other heavy metals.

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.

Investigating Food Intolerance

Wednesday, May 27th, 2009

Investigating Food Intolerance

COLICKY BABIES
If you have followed the measures described on pp. 78-9 but have had little or no success in reducing colic symptoms so far, it makes sense to look into the possibility of a food sensitivity reaction (either intolerance or a mild allergy) to food proteins. This is a very different problem from lactose intolerance (an inability to digest the milk sugar, called lactose, due to a shortage of lactase - see p. 79), although the two can get entangled, creating a complex and confusing set of responses.
The complications arise because, when there is diarrhoea as a result of allergy or intolerance (or from any other cause, including infections) it temporarily strips the gut of its lactose-digesting capacity. This problem is called secondary lactase deficiency, and it will correct itself quite quickly once the real cause of the diarrhoea is eliminated.
Unfortunately, the routine medical tests for lactase deficiency do not distinguish between this temporary problem and the much rarer primary lactase deficiency, which is inherited and life-long.
So if your child has had these routine tests, and you have been told that they show primary lactase deficiency, it remains possible that the real problem is a reaction to milk proteins (or proteins from other foods), and that the lactose intolerance is an effect of this, which adds to the diarrhoea, but is not the root cause of it. If so, eliminating the offending food from the baby’s diet (or the mother’s) will produce impressive results, whereas reducing or eliminating lactose only helps a little.
The purpose of the dietary investigations described here is to discover which foods are causing problems for your baby. In the case of bottle-fed babies, the answer is usually cow’s milk – and this is often the culprit for breast-fed babies too, but not necessarily.
For a breast-fed baby it can be any food that the mother is eating. A tiny proportion of what the mother consumes goes through into the breast milk, and these few molecules of food are enough to provoke a reaction in the child.
Bottle-fed babies
For bottle-fed babies, proceed as follows:
•    Change to an alternative milk-free formula (see box on p. 66). Wait two weeks before concluding that there is no improvement – recovery can take time – and try another type of formula before you decide this is not the answer.
•    If there is no joy with alternative infant formula, consider the possibility of relactation: stimulating the flow of your own breast milk once again. Breast-feeding support groups (see page 255) can give you advice. Avoid all dairy products while breast-feeding and take a calcium supplement.
For babies who are old enough, and who have severe symptoms, early weaning is one option, but this must be done very carefully:
•    Keep all dairy products out of the baby’s diet – read labels carefully on prepared foods and know all the different names used for milk (see page 173). Test beef cautiously as it shares some proteins with milk.
•    To avoid new food sensitivities developing, keep eggs, fish. wheat, chocolate and oranges off the menu until the child’s first birthday, then introduce them gradually. Avoid peanuts and other nuts for three years if possible.
•    Keep maize (corn) out of the diet for the first six months, because it is a common ingredient in formula feeds, and the child may have become sensitive to it. Note that some medicines contain corn syrup, but this will only affect those who are very sensitive. A pharmacist can check the full list of ingredients in medicines, and suggest alternatives.
•    No food should be given to the baby every day, or in large amounts. You can use unusual starchy foods, such as sweet potatoes, yams, culnoa and millet (see p. 195), to ring the changes. These all make excellent baby foods.
•    Never force a child to eat any food that is disliked. Try serving it again, once or twice, but give up if there are still fierce objections to the smell or taste – these are often a sign of intolerance or allergy.
•    Ask your doctor to refer you to a paediatric nutritionist so that the diet can be checked. A calcium supplement will probably be needed. Other vitamins or minerals may also be lacking.
Breast-fed babies
For breast-fed babies, the approach is quite different – the main focus here is on what you, the mother, eat and drink.
Firstly, start keeping a food diary, and a record of the baby’s symptoms. Are there any detectable patterns? Does the colic get worse if you drank red wine on the previous day, for example? Note that sometimes the time-gap is more than a day, but it should be reasonably consistent for any one food.
At the same time, eliminate all items other than breast milk from the baby’s diet, including:
•    any solids (e.g. baby foods)
•    fruit juice
•    medicines or vitamin drops that contain other ingredients (e.g. colouring or corn syrup)
•    nipple creams containing arachis oil (peanut oil).
Ask your doctor or pharmacist for alternative versions of medicines or vitamins, without added ingredients. Give boiled water to make up for fruit juice. Wait a week or so to see if things improve.
For the next stage, cut out coffee, tea and all alcoholic drinks. Allow a week for this, and continue with the food/symptom diary meanwhile. If there is no improvement, go on to the next stage, while still avoiding coffee, tea and alcohol.
For the next stage, compile a list of suspect foods, based on your food diary. Add to this list:
•    cow’s milk and all milk products
•    any foods that you craved when pregnant
•    any foods that you normally eat in large amounts
•    anything you dislike but have been eating because it’s ‘good for you’ or ‘good for the baby’
•    any of the following foods if you eat them regularly: eggs, wheat, oranges and other citrus fruits (lemons, grapefruit etc.), tree nuts, peanuts, fish, chocolate, chicken and beef.
Once you have your list prepared, talk to your doctor. Say that you would like to try eliminating cow’s milk for two weeks to start with, and then – if the colic has not cleared up – all the other foods on your list as well (again, for two weeks). You will need to take a calcium supplement. If there is strong opposition to your plans, based on a fear that your diet will be inadequate, ask for a referral to a nutritionist. Obviously this needs to be arranged promptly. The fear of under-nutrition, which is dangerous for both yourself and the baby, is a very reasonable one, but with sensible precautions any mother can safely carry out this investigation.
Eat at home during this time, as you cannot possibly know all the ingredients in cafe or restaurant meals. Read the labels on packaged meals and watch out for synonyms (see pp. 172-4).
If your baby recovers, and you want to pinpoint the problem food so that your diet becomes less restricted, you can test foods individually. Wait until there has been no sign of colic for a week. Choose one food and eat a portion every day for a week. If the colic does not reappear, cut out this food again and choose a second food to test – again, eat this daily for a week. Stop eating the food sooner if the colic returns. (Foods that proved safe can be reintroduced again later, but you need a break after the testing week.) Test cow’s milk last.
Some babies get better during the exclusion phase but do not respond to any of the foods when tested. The temporary break from the problem food seems to be all they need to lose their sensitivity. In such cases, the mother can go back to an unrestricted diet, but not to exactly the kind of diet she ate before – no food should be eaten every day, nor in large quantities, or the colic may return.
Many babies get over their sensitivity after one or two months without the problem food, so it is worth testing again after a while, especially if you are eating a very restricted diet.
Where cow’s milk turns out to be the offender, goat’s milk or sheep’s milk might be tolerated, but wait until the baby is completely free of symptoms and experiment cautiously. Alternatively, drink one of the new milk substitutes now available (see p. 183).
If the baby clearly responds to a food in the mother’s diet (for example, cow’s milk or peanuts), this food should be given cautiously when first introduced to the child after weaning, in case he or she has a true allergy to it. An allergy test may be helpful in deciding whether to introduce the food at all.

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.

Dealing with Emergency in Allergy

Thursday, May 21st, 2009

Let’s hope it never happens - but if it does, knowing what to do could make the difference between surviving and not surviving. The sensible thing is to read these pages - or whichever parts are relevant to you or your child - before you encounter an emergency. It is often helpful to rehearse the procedure in your mind and actually imagine yourself going through the actions described here.
Find out in advance what the local ambulance service is like, and ask your GP for advice about who to contact in an emergency. (If you have latex allergy, check in advance that all local ambulances carry a latex-free kit.) These are the options:
• Call your GP.If the doctor is nearby and the hospital or ambulance station a long way off, this may be the best decision. Doctors in rural areas may have supplies of adrenaline for emergency treatment, and oxygen for those suffering a severe asthma attack.
• Call an ambulance. Where the local ambulance service is dependable, this is always the best option. The ambulance crew will have adrenaline and oxygen.
• Go by car or taxi to the nearest hospital
emergency department. This is not usually a
good plan, because your condition may quick-
ly get worse, and you have no emergency
treatment available. But there may be situa-
tions where it is a sensible decision. Emergencies can occur when you are away on holiday or business. Never stay anywhere without a phone – check that it is working as soon as you arrive. Make sure you have the number of a local doctor and know where the nearest hospital is. A remote holiday cottage can be a dangerous place to suffer an asthma attack or anaphylactic shock.
Anaphylactic shock
This is an extremely serious emergency, requiring immediate medical help. The signs of anaphylactic shock are listed on p.58. In the case of food allergy, there are additional signs in the mouth, lips and throat (see p. 62). Use adrenaline (epinephrine) straight away if you have it – but get emergency medical help as well. With injectable adrenaline (an EpiPen or Anapen – see p. 150), remove the cap and jab firmly into the outer thigh, going straight through any clothing. Never inject into any other part of the body – this can be dangerous.
If you have an adrenaline inhaler (see pp. 155-6) you can use this first to treat symptoms in the mouth, throat and airways, and then use the injector if you still have symptoms. (Improvise a spacer – see p. 100 – if there is difficulty in inhaling the adrenaline.) Anyone whose reactions tend to be severe should use the injector first and follow up with the inhaler if necessary. Overdosing with adrenaline is possible, and can be fatal, but using the inhaler as well as the injector is safe as long as you don’t have a heart condition (see pp. 155-6).
If you do not improve after using the injector, a second one can be used, 10-15 minutes later.
In situations where medical help is not yet available and the symptoms are not abating, another shot of adrenaline can be given every 15-20 minutes. But the maximum number of shots recommended by your doctor should never be exceeded. Keep count of how many you’ve had, and tell medical staff.
An asthmatic who does not have an adrenaline inhaler can use a beta-2 reliever inhaler such as Ventolin (see p. 152) as well as the adrenaline injection, although it probably won’t help very much.
Suppose you know for sure that you have encountered your allergen, but you don’t have any symptoms yet? In Britain, the usual advice is to wait for symptoms, but doctors in the United States say go ahead and use the adrenaline injector if you have reacted very badly in the past. In general, for people with no other health problems, it is better to give an adrenaline injection which isn’t needed than to delay giving one that is needed. Delaying the use of the injector may mean that the reaction gets out of control. Some people put off using the injector because they think it should be saved for when they ‘really need it’. In fact the adrenaline works just as well if you have used it on previous occasions.
Following anaphylactic shock, you should be kept in hospital for 6-12 hours even when everything seems fine. Attacks have recurred as much as eight hours later. Corticosteroids reduce the chance of this happening – ask if these have been given. If you are discharged early and it is a long journey home, consider waiting in the hospital, or nearby, until eight hours after the original reaction.
First aid for anaphylactic shock
A badly swollen tongue or throat can cause suffocation. If there is visible swelling and the person is unconscious or turning blue, try to keep the top of the trachea (the main airway leading from the throat) open. Use the handle of a spoon – one that has very smooth edges. Slide it carefully over the top of the tongue and into the throat. Press down gently but firmly to open the airway.
Someone who is feeling faint or dizzy, or losing consciousness, or (in the case of a child) becoming very pale and floppy, may be suffering from a dangerous drop in blood pressure. He or she is more at risk of a fatal collapse if in an upright position, because not enough blood is reaching the heart. The worst thing is to stand up suddenly, or to move (or be moved) quickly from a lying to a sitting position –death can follow within seconds. The best thing is to lie down, preferably with the legs resting on cushions or a stool so that they are above the torso, and with the arms raised above the chest. Adrenaline can be given while in this position. A stretcher should be used to get the patient to an ambulance.
Latex allergy and emergency treatment
If you have anaphylaxis due to latex allergy, going to hospital can be alarming, as you may suffer further reactions to latex gloves or equipment. Some patients with latex allergy have had such bad experiences in ambulances and hospitals that they become fearful of using their adrenaline injector, since this means they must go to the hospital afterwards. They delay using the injector, which makes the situation worse. Some doctors are now giving such patients all the medicines and training they need to manage their anaphylactic shock themselves, so that they don’t need to attend hospital.
A person who has lost consciousness should be lying down on their side in case they are sick (this reduces the chance of them inhaling their vomit). The same goes for anyone who feels nauseous.
On the other hand, if the major problem at the outset is difficulty in breathing (as it generally is in children) a sitting position is better.
It is unusual for both faintness and severe breathing problems to be present at once. If this occurs, the patient should lie down, and if there is swelling in the throat, a spoon should be used (see left) to keep the airways open.
Insect-sting allergy
If you don’t have an adrenaline injector, get medical help immediately.
If you’ve had a cutaneous systemic reaction (see p. 60) in the past, use the adrenaline injector if there is any difficulty in breathing, hoarseness, stomach cramps, diarrhoea, nausea, faintness, dizziness or confusion. If you are unsure, remember that, unless you have a heart condition, it is usually better to overreact (i.e. use the adrenaline unnecessarily) than under-react.
If you’ve had a severe systemic reaction (i.e. anaphylactic shock) in the past, use an adrenaline injector at the first sign of any reaction other than immediately around the sting.
If there is a honeybee stinger left in the skin, scrape or flick it out sideways using a fingernail, knife blade or credit card – the venom sac is attached and will go on injecting venom for up to 10 minutes if you leave it there.
Don’t try to pull the stinger out – this squeezes the venom sac and pumps more venom into the skin.
Get emergency medical help, and follow the other measures for dealing with anaphylactic shock (see left).
Don’t go alone
If you suffer vomiting or diarrhoea during anaphylaxis, and have to go to the toilet, tell someone to call an ambulance and take someone else with youto the toilet. Do not go in alone and lock the door, in case you collapse.
Asthma attacks
Even those with mild asthma, who have never had a serious attack before, can quite suddenly get into difficulties and require emergency treatment. Don’t be over-anxious about this, because it is unlikely to happen – but do be prepared. Not having your reliever inhaler with you when a severe attack starts is a recipe for disaster – always take it, wherever you go.
Deal with an attack promptly. The sooner you act, the fewer drugs you’ll need in the long run to control the attack. Most asthmatics wait too long and then under-treat their asthma.
The important thing is recognising an asthma attack, and knowing when it is getting out of control. Not all attacks are the same – some come on fast, some come on slowly.
Rapid asthma attacks come on in a matter of hours. You may have been fine all day, but then start to feel very breathless and wheezy, or begin coughing badly. Less than an hour later, despite using the reliever, the breathlessness is worse and it is a struggle to speak or walk across the room. This is a severe attack: don’t delay in getting medical help.
Slow asthma attacks come on over a period of days. At first you are more breathless and wheezy than usual, and your reliever inhaler is not helping much. Asthma wakes you up at night, and you are far more breathless than usual in the morning. This could be the beginning of a severe attack, so don’t delay in getting medical help. If you get to the point where your asthma is disturbing your sleep every night, and in the morning you have difficulty in speaking or walking about, this is a very serious situation – you must see your doctor or go to the hospital now.
A few asthmatics have great difficulty recognising when they are increasingly breathless, and for them, using a peak-flow meter (see p. 97) every day is essential. Indeed, most asthmatics find
Recognising an asthma attack in a very young child
With a young child, these signs indicate a severe asthma attack:
• the nostrils are flared
• the shoulders are unusually high
• the child can say only one or two words between breaths
• the ribs are pushed out, and the spaces between the ribs, and below the chest cage, are sucked in during breathing
• you can hear wheezing (a whistling noise)
• the lips, tongue or fingernails are blue.
If wheezing stops, without any other apparent improvement, this is a very bad sign — it may mean that the airways are now so narrow that no air is passing through them. This is called a ’silent chest’, and indicates an urgent need for medical attention.
that monitoring peak flow is a valuable way of spotting attacks in advance. However, if your peak flow seems normal, and yet you feel breathless and have a tight feeling in your chest, pay attention to your symptoms and get medical help.
Your response to your reliever inhaler is another helpful sign assessing asthma attacks. Things are serious if:
• the reliever inhaler does not seem to be working at all within 10 minutes of taking a puff
• it does not work as well as usual
• it works, but the effect wears off in less than three hours. If you have an asthmatic child, give everyone who normally takes care of the child detailed written instructions for recognising and dealing with an asthma attack. People forget verbal instructions especially in an emergency. A child who is exhausted or upset c. an attack should always be given medical care.
Taking action
If your reliever inhaler is not working well (see above), take another puff to open up your airways – and then take further action. as described below.
If you seem to be in the early stages of a slow asthma attack check your management plan, and if your peak flow has fallen below the recommended level, double the dose of inhaled steroids (twice as many puffs each time) now. Add any other medicines (e.g. steroid tablets) as recommended by the management plan.
Those who don’t have a peak-flow meter or management plan should double the dose of inhaled steroids and make an urgent appointment to see the doctor.
If you are suffering a rapid attack, or a slow attack that has got out of control, you need emergency medical help. Ring for an ambulance, ring your doctor, or go to the hospital – the ideal course of action will vary, depending on where you live (see p. 98).
Use your reliever inhaler until medical help arrives. You can take a puff every 5-10 minutes if needed, but keep a count of how many puffs you’ve had and stop after 30. Some doctors suggest taking up to 30 puffs all at once. (If you have a heart condition, this dose might be dangerous: follow your doctor’s advice.)
If it is difficult to inhale, use a spacer – this can make all the difference, especially for children.
You can improvise a spacer from a plastic cup, a plastic bottle, or a paper bag. Make a hole in the bottom of the cup or bottle, or in one corner of the paper bag, and insert the mouthpiece of the inhaler here. The open end of the cup, bottle or bag goes in or over the mouth – with the bag, you have to bunch it up and hold it around the mouth. Squirt the inhaler repeatedly into the improvised spacer, while breathing steadily in and out.
The six golden rules for asthma attacks
• Breathe as slowly as possible and concentrate on breathing out, not on breathing in. Exhale as fully as you can and your in-breath will follow automatically.
• Never panic – if you do, you may start hyperventilating, and this makes matters much worse (see p. 226). Panicky parents are the worst possible thing for an asthmatic child during an attack.
• Adopt a position that makes breathing as easy as possible. Propping your arms up at about shoulder height can help – for example, sit back-to-front on a dining chair, with your arms folded and resting on the back. Or put pillows on a table, sit in an upright chair, and rest your head and arms on the pillows. Don’t lie down, as this makes matters worse. Open a window, as long as the air outside is not cold, polluted or loaded with pollen.
• Avoid factors that can make an asthma attack worse, for example, vigorous activity, cold air, irritants and allergens.
• Drink plenty of water, fruit juice or other liquids as a lot of water is lost through the surface of the airways during an asthma attack, and you can become dehydrated.
• Don’t take anything to help you sleep, even herbal pills. If your asthma gets worse during the night, you need to wake up so that you can get more air.
After an attack
Asthmatics who have suffered a severe attack are occasionally sent home from hospital before they are completely better. A few people have died as a result of being discharged too soon. So if you feel breathless or otherwise unwell after you leave hospital, don’t hesitate to go back – or seek other medical help.
See your GP or specialist within a few days of any emergency treatment. Don’t be over-confident just after a severe attack – this can be a very vulnerable time. Take more rest than usual and drink plenty of fluids, as you may be dehydrated. Keep taking your preventer inhaler at the increased dose – reducing the dose now could lead to another severe, possibly fatal, attack. Keep taking steroid tablets if you have been given them.
If you produced a lot of mucus during the attack, try to clear it, but without violent coughing. Mucus can sometimes form solid plugs which block small airways. Treatment by a physiotherapist would help, and expectorants – drugs which help loosen mucus –can also be useful (ask your pharmacist about these). Don’t take ordinary cough medicine (see box on p. 163). There are also some breathing exercises which can help to clear mucus (see p. 231).
An asthma attack represents a chance to learn more about preventing asthma – so think about what went wrong. Had you forgotten to take your preventer inhaler regularly? How long is it since you had your medicines reviewed by the doctor or asthma clinic? Have you been using your peak-flow meter daily? Were you exposed to a high dose of allergen or an irritant?
A reaction to aspirin-like drugs
Aspirin sensitivity can begin quite suddenly in someone who has previously taken aspirin without trouble. If you have unexplained chronic urticaria, or polyps in the nose, plus asthma and/or rhinitis, the development of aspirin sensitivity at some time in the future is a distinct possibility (see p. 151).
A sensitivity reaction to aspirin or aspirin-like drugs usually begins between 30 minutes and two hours after the drug is taken. You will have some or all of these symptoms:
• a runny or badly blocked nose, and red eyes
• a feeling of warmth, flushing and sweating
• a general rash
• a sensation of tightness in the chest, a dry cough, increasing breathlessness
• malaise and exhaustion
• vomiting or diarrhoea
• swelling (angioedema) and/or nettle rash (urticaria). If you have such symptoms get emergency medical help immediately because the reaction can quickly develop into severe asthma, shock, collapse and unconsciousness.
If you have asthma, use your reliever inhaler as much as required (up to 30 puffs) until medical help arrives. Anyone who has an adrenaline (epinephrine) auto-injector, or an adrenaline inhaler, can use this as well – up to 30 puffs of the inhaler, or whatever maximum dose is given in the instructions. Tell the ambulance crew and doctors exactly what you have taken.

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.