Protecting Children Having Allergies
No single factor lies behind the allergy epidemic — the causes are many and various (see p. 20). What this means for parents interested in allergy prevention is that there is no
single measure which will ensure that your children do not develop allergies. Instead there are a great many different things that can be done, each of which reduces the risk to
some extent. The more of these you do, the lower the risk becomes.
Avoiding allergens
Starting before the birth is best, if you want to reduce allergen exposure for your child (see p. 240). But if you have missed the boat with that one, don’t despair – there is
still a lot to be gained by reducing allergen exposure at a later stage.
If you are ridding your home of allergens after the child’s birth, bear in mind that things will get worse before they get better– there will be a temporary surge in airborne
allergen as a result of the clean-up operation, and you will need to protect the child from this. The best strategy is for the child to be away for a few days while the work is
done, especially if you are taking out carpets, furniture or mattresses. Remember to protect yourself as well, if you are allergy-prone (see p. 109).
One of the most important steps you can take to reduce allergen levels is improve the natural ventilation of your home. This lowers the humidity (assuming you don’t live in an
extremely humid climate), which helps combat both moulds and dust mites. Ventilation also flushes out allergens in the air, especially cat, dog and mould allergens. Half the
problem with modern houses is that the airtight seals around doors and windows, introduced to conserve heat and save energy, turn the indoor air into a rich stew of allergens
and irritants.
House-dust mite
Avoiding high levels of house-dust mite in the home is one of the most valuable things you can do to reduce the risk of allergies in your child. Not only is house-dust mite a
powerful allergen in its own right, it may also act as an agent provocateur as far as the immune system is concerned (see p. 12), and may help to initiate allergic reactions to
other potential allergens – such as those from pets or indoor moulds.
Even if you do nothing else to protect your new baby from mite allergen, at least buy a new mattress and pillow for the cot, with ready-fitted allergen-proof covers. Do the same
for the portable crib, if you have one. Choose anti-mite products that are designed for babies and are guaranteed safe – there is a risk of suffocation with some loose covers
sold for older children and adults (see p. 245).
You may want to eliminate house-dust mite from your own bed as well as the baby’s, because there will probably be times when you take the baby into bed with you for a feed or a
cuddle – and times when, as a toddler, he or she just barges in! It is good to know that your child is still breathing air free from dust-mite allergen in these circumstances.
Deal with your own bed as soon as you can. Some doctors believe that lowering your exposure to dust mite during pregnancy may reduce the risk of sensitising your baby before
birth (see p. 241).
When taking anti-mite measures with your own bed, make sure that there is no risk of suffocation to the baby from the allergen-proof materials used. Microporous membranes based
on plastic could, if sucked onto the baby’s face during sleep, cause suffocation. Loose covers on duvets are worrying in this respect. Buy a new duvet with a built-in
allergen-proof cover, for preference, or a duvet that can be laundered at 60°C or above.
All the other measures for combating dust mites, described on pp. 114-17, will help to protect your child. Buy a good anti-allergen vacuum cleaner if you possibly can, and keep
your baby out of the room while vacuuming if you can’t (open the windows too). Make sure the baby only has new soft toys, preferably washable ones (see p. 116).
It is also an excellent idea to reduce dust-mite levels in the carpets and soft furnishings (see p. 117), because children tend to have very close contact with these in their
early years. A crawling baby, motoring enthusiastically around the sitting room floor, is stirring up the stockpile of dust-mite allergen that is found in any carpet, and
inhaling it in full measure. An adult walking around the same room has a far lower exposure, because dust-mite allergen, being relatively heavy, stays near the ground.
The best option is to go for non-carpet flooring, which doesn’t encourage dust mites. Parents tend to worry about the hardness of this, for a baby or toddler. In fact babies are
far more robust than we generally believe, and a hard floor is no problem for a small child who has never known the luxury of carpeting.
If you really hate the idea of your baby having anything other than carpet to play on, the next best option is to get new carpet, so that you start with zero dust mites. You
must then prevent dust-mite numbers from building up too much, by means of good ventilation, or with the use of a powerful dehumidifier (see p. 117).
Although the first year is the most vulnerable time for your baby, you mustn’t let your guard drop too much as time passes. The moment when a toddler moves from a cot to a ‘big
bed’ is sometimes the beginning of allergy symptoms because, after carefully protecting their child from dust mites in infancy, parents then put him or her into a bed with a
used mattress. This sudden exposure to a high dose of
dust-mite allergen can be the start of asthma. Get a new mattress if you can, and put allergen-proof covers on it. Alternatively, put allergen-proof covers on the existing
mattress.
Moulds
Mould spores are another potent allergen, and you should avoid bringing up a vulnerable child in a damp house if you can, because moulds will be growing there in abundance. Some
new research suggests that heavy exposure to mould allergens in childhood makes allergies in general much more likely. Even in a house that is not obviously damp, it is a good
plan to reduce indoor humidity (see p. 119). Carpets and furnishings that are full of mould spores (see p. 122) should be replaced.
Pets
What about pet allergens – should you find another home for your cat or dog when you are expecting a baby? This is a difficult question because the latest research shows that
pets are a double-edged sword as far as allergies are concerned.
A baby with allergic tendencies who is born into a house with a resident cat or dog is more likely to show allergic reactions to cats or dogs some years later. On the other
hand, there is research showing that having a pet in the house reduces the risk of allergies overall, especially for a child with no brothers or sisters. This is probably
because the pet boosts household levels of endotoxin (see p. 21), and generally makes the environment less hygienic for the child, fulfilling the same anti-allergy role as
brothers and sisters would in the early life of a child (see p. 246).
If you are planning to give your child the kind of grubby childhood that seems to protect against allergy (see p. 246), the additional protection provided by a pet is probably
unnecessary. Or, you could view your pet as having both pros and cons, and decide to keep it, while implementing all the other anti-allergy measures described here. If you do
this, ensure that the house is well ventilated (so pet allergens don’t build up to very high levels) and keep the pet out of the child’s bedroom so that he or she is not
breathing huge amounts of pet allergen while asleep. You could also wash the pet regularly (see p. 125) to reduce allergen levels.
If your child begins to show any signs of allergy to the pet, you must then find it another home.
Avoiding irritants
As well as increasing ventilation and eliminating cigarette smoke from the home completely, it may be worth evicting certain specific items that produce irritant gases.
The main ones are:
• gas cookers (if you can’t afford to switch to an electric cooker, at least improve the ventilation in your kitchen as much as possible)
• easy-clean plastic wall coverings and flooring
• materials such as chipboard and MDF, which give off formaldehyde.
The evidence regarding the possible role of these in increasing the risk of allergies and asthma is described on pp. 128-9. In addition, although there is no evidence on this
point, common sense would suggest getting rid of any plastic or lacquered items that have a powerful smell.
Generally speaking, although traffic pollution can act as an irritant, it seems to play a lesser role in causing allergies and asthma than most people imagine. However, it may
sometimes play a part, especially if there are high levels of diesel fumes in the air (see p. 131).
Infections - friend or foe?
A large group of Italian military cadets were recently studied by doctors interested in the causes of allergy. By taking blood samples and testing them for antibodies to common
infections, the doctors could see what diseases the men had been exposed to early in life. At the same time, the young conscripts were assessed for allergies.
Allergies were least frequent among the young men with antibodies against three common infections that are dispersed via food and faeces – Hepatitis A, Toxoplasma gondii and
Helicobacter pylori. Only one in twelve of the cadets in this group had allergies.
Among the men with no antibodies against any of these infections, the rate of allergy was nearly three times as high – one in five of these cadets had allergies.
The doctors who carried out this experiment believe that these three infections are not necessarily important in themselves, but that they identify individuals who were ‘reared
in an environment that provides a higher exposure to many other orofecal or foodborne microbes’. In other words, they grew up in the kind of household where washing your hands
before meals wasn’t considered too important.
This study adds to the growing body of evidence (see p. 21) which shows that an over-clean environment during childhood encourages the development of an allergic disposition.
Those with lower rates of allergy include:
• children raised on farms with livestock. The more exposure the children have to farm animals, the less the likelihood of them developing allergies.
• children from homes with high levels of bacterial endotoxin in the household dust (see p. 21)
• children who have fewer baths, and wash their hands less often (see p. 21)
• children with brothers and sisters, especially those with older siblings. Some of the protection here may be due to the impact of the mother’s hormones and immune system
on the foetus in the womb: these effects change with successive pregnancies. But close contact with older siblings, and thus exposure to more microbes, probably plays a part.
• children who go into kindergarten, nursery school or day care with other children at an early age – this is only valuable for children without brothers and sisters
• children with pets at home – the benefits are much more pronounced for children without brothers and sisters.
The Italian study is especially important because, for the first time, it gives detailed information about the kinds of infections that make a difference in allergy prevention.
The military cadets were also checked for antibodies to measles, mumps, rubella, chickenpox and herpes. None of these infections gives protection against allergies – only
infections carried in food and faeces do.
Exactly what practical use you make of these discoveries is up to you. For most of us, the importance of hygiene was so firmly instilled during our own childhood that it is
quite hard to suddenly become more relaxed about it. But do let your children play in the garden, if you have one, and don’t worry so much about how dirty they get. Encourage
them to do some gardening – medical researchers believe that harmless bacteria in the soil may be particularly important in educating the immune system away from allergies (see
p. 21). Let them play with pets, as long as the animals are not carrying harmful parasitic worms (talk to your vet about whether pets should be treated for parasites). Ease up
or, hand-washing and, if this is your first baby, make sure he or she plays with other children as early in life as possible.
A few chest infections do seem to increase the risk of asthma, notably Respiratory Syncytial Virus (RSV). If this Infects babies, it provokes an IgE-reaction (see box on p. 12)
which may encourage the development of allergies. Unfortunately, there is very little you can do to protect your child from this common virus, but it makes sense not to take the
baby to a hospital for unnecessary trips (visiting relatives, for example) because RSV infections are often picked up in hospital.
Taking care with antibiotics
The possible role of antibiotics in making allergies more likely to develop is an exceedingly controversial topic. Before making any practical decisions in this respect, you
must consult your doctor. Never go against your doctor’s advice, if he or she thinks that antibiotics are necessary.
Several different studies have now produced evidence of a link between antibiotic use before the age of one or two, and the later development of allergies, asthma or both. The
best of these studies was carried out by doctors in Oxford, who followed 1900 children up to the age of sixteen. Among children at risk of allergy (because their mothers had
allergies) taking antibiotics before the age of two was linked with an increase in the rate of allergy from 32% to 54%. The more courses of antibiotics a child received, the
greater the risk.
The type of infection for which the drugs were prescribed was not important, as far as the risk of allergy was concerned, but the type of antibiotic did make a difference.
Broad-spectrum antibiotics, which kill a wide range of bacteria, were more risky –suggesting that the depletion of friendly bacteria in the gut (see p. 204) could be responsible
for increasing the allergy risk. Penicillins seemed less likely to promote allergies than erythromycin or cephalosporins.
This research is not widely known, as yet. And because there is a widespread assumption that giving an antibiotic can do no harm, even if it is unnecessary, antibiotics are
sometimes prescribed when they serve no purpose. In particular, antibiotics are often given for virus infections, especially in childhood, despite the fact that antibiotics are
of no value whatever against viruses. Research shows that doctors are sometimes responding to pressure from anxious parents when they prescribe antibiotics – it is difficult for
some parents to accept that a virus infection cannot easily be treated and just has to ‘run its course’. (Although there are drugs that combat viruses, these are expensive and
produce unpleasant side effects – they are reserved for very serious virus infections such as hepatitis.)
Obviously. when a child needs antibiotics to deal with a serious infection there can be no question about giving them. This is why you should always follow your doctor’s advice.
But it is also worth asking the doctor the following questions before giving antibiotics to your child:
• are you sure that this is a bacterial infection, and not a virus infection?
• would it be possible to do tests and check that it is a bacterial infection, before prescribing antibiotics?
• what is the chance of the child overcoming the infection without antibiotics?
• would it be dangerous to wait and see if the infection clears up naturally?
Vaccination
The same Oxford research team that investigated antibiotics (see left) also looked at the question of vaccination and allergy. They found a link between vaccination for
pertussis (whooping cough) and increases in asthma, eczema and hayfever. However the increases were not large, and a study from Sweden found that whooping cough vaccination did
not have any effect on rates of allergy and asthma. And researchers in Ethiopia have found that whooping cough vaccination actually reduces the risk of allergy in their country.
This is clearly a complex issue. The contradictory results from different parts of the world suggest that the ‘big picture’ is what counts here – the overall combination of
childhood infections, antibiotic treatment and exposure to harmless bacteria such as those in the soil or from animals. Depending on this big picture, vaccination against
whooping cough may push the allergy risk one way or the other.
There are many other arguments both for and against vaccination and, given our current state of ignorance about the possible effect on allergy, these other considerations are
probably more relevant. Discuss the matter in detail with your doctor before making a decision.
Doctors in Japan recently tried a very simple experiment in allergy prevention. They chose babies suffering from atopic eczema who were allergic to foods, but not allergic to
house-dust mite. Dividing the babies into two groups, the doctors put special allergen-proof covers, designed to protect against house-dust mite (see p. 115), on the mattresses
of all the babies in the first group. Babies in the second group were given ordinary cotton covers.
When the babies were one year old, they were tested again for allergy to house-dust mite. Two out of three children in the second group now gave a positive skin test to
house-dust mite.
By comparison, only one in three of the children from the first group gave a positive skin test. In other words, using the anti-allergy covers for these high-risk children had
cut by half the number who developed an allergic reaction to dust mite.
As this experiment shows, even if a child has already developed allergies, it is not too late to bring protective measures into play. Indeed, an allergy problem in infancy, such
as atopic eczema, can be seen as a warning sign to parents, telling them that they should reduce the child’s exposure to allergens as much as possible.
As well as reducing dust-mite levels, you should minimise your child’s exposure to moulds at home by limiting indoor humidity (see p. 119) and cleaning up any existing mould
growth (see pp. 122-3). This will lessen the chance of mould allergy developing.
Try to avoid staying, even temporarily, in any house that is damp or has old carpets and mattresses. When you are moving house, or carrying out any kind of renovation work,
remember that this will stir up a lot of dust-mite and mould allergens. Protect your child by arranging for a stay away from home.
This pro-active approach should not just apply to airborne
allergens, but also to food, in the opinion of some experts. They
suggest that any child with a true allergy to cow’s milk or egg
should not be given peanuts, tree nuts, fish or shellfish until three
years of age, to avoid sensitisation to these potent food allergens.
Pets are a more difficult issue, with both pros and cons as
regards allergy-prone children (see p. 245). If you decide to keep
your cat or dog, always ventilate the house well, and wash the animal regularly if you can (see p. 125). Be alert for your child developing an allergic reaction to your pet –
don’t turn a blind eye to the symptoms, as parents sometimes do because they are reluctant to accept that the child has become allergic to the family’s much-loved pet. If your
child does develop an allergy to the pet, the best option is to find the animal another home as quickly as possible (see p. 124).
Breast-fed babies with atopic eczema
Although breast-feeding is a good way of protecting children against atopic eczema, it is no guarantee. Sometimes babies become sensitised to food, in spite of being breast-fed,
and then they may react to traces of that same food, eaten by the mother and coming through in her breast milk.
Skin-prick tests (see p. 91) may help to identify the foods responsible for the eczema. Otherwise, a simple elimination diet by the mother, as used for colic (see p. 203), may
pinpoint the offending food. Keeping that food out of the mother’s diet will often clear the baby’s eczema.
Sometimes a breast-fed child’s eczema remains severe, despite the elimination of suspect foods from the mother’s diet. In this case, what should be done? New research from Or
Erika Isolauri – a staunch advocate of breast-feeding – suggests that the best option at this point is to stop breast-feeding promptly. Her research team found that breast-fed
children with persistent eczema had a slower growth rate. If these babies are switched to hypoallergenic formula – either an extensively hydrolysed formula or an artificial
amino-acid formula (see box on p.66) – their eczema symptoms usually subside, and their growth picks up.
Is vaccination safe for those with allergies?
The influenza vaccine and a few others (e.g. yellow fever) are grown in eggs and are not usually given to people with egg allergy. Measles vaccine is grown in cells taken from
eggs and may contain a minute trace of egg allergen, but only those who are extremely sensitive will react: there should be resuscitation equipment available for children who
have had anaphylactic reactions to egg and for those with severe asthma as well as egg allergy. Some vaccines come in vials with latex seals that are designed to be pierced by
the needle of the syringe. A different method should be used for latex-allergic patients. Smallpox vaccine (for bio-terrorism threats) is dangerous for children with atopic
eczema.
Never too late?
The role of modern ultra-clean lifestyles in promoting allergies is now well established (see p. 21). If your child already has allergies, it may seem as if these discoveries
have come too late to help —but that is not the case. Some research suggests that the battle for supremacy between Th1 and Th2 cells (see p. 11) — the unseen power struggle
which decides whether a child will be allergy-prone — is not really settled until some time between the ages of five and seven years. So there is still some potential for
intervening right up to this age. Some studies have suggested that the immune system can be pushed away from an allergic disposition at an even later age, right into adulthood,
by exposure to endotoxin, a bacterial product found around livestock and in `lived-in’ homes.
Several research groups are working on vaccination strategies (for example, using extracts of soil bacteria) that might also be able to achieve this. The initial results are
promising and they suggest that these vaccines can even help adults with allergies. Unfortunately, such treatments will not be available for many years. In the meantime, you can
probably reduce your child’s chance of developing new allergies, and perhaps make the existing ones less severe, by easing up on hygiene (see p. 246).
Fresh air and exercise
With the boom in watching TV and videos, and playing on computer games, some modern children hardly go outdoors at all. As far as allergies and asthma are concerned, there are
two big disadvantages to being a juvenile couch potato. For a start, the couch is also home to dust mites in their millions, and secondly the child is not running about and
using his or her lungs to the full. Airways that are never stretched (because the child never gets out of breath) lose their youthful flexibility in time. Once this has
happened, the airways can never be stretched to their full capacity. Some doctors believe that this may make asthma more likely to develop, or help to make it more severe once
it has developed. Inactivity also encourages obesity, which increases the risk of asthma developing.
Getting outside and running around, or engaging in other vigorous exercise, should be encouraged for any child with allergies. Obviously, you should balance this against the
need to protect the child from pollution peaks and (if your child has hayfever) pollen peaks. Children with exercise-induced asthma should use their reliever inhalers to allow
them to take exercise (see p. 41).
Keep the air at home free from irritants such as nitrogen dioxide (see p. 128), formaldehyde, air fresheners, paint, polish and strong-smelling cleaning fluids. These may
encourage new allergies to develop, and can make existing asthma worse.
Medical treatments
Antihistamines may have a preventive role in very young children with allergies. A study of one- to two-year-olds with atopic eczema found that the antihistamine cetirizine,
taken daily for 18 months, halved the chances of the children developing asthma later.
The children who benefited in this study were those with several risk factors for becoming asthmatic. They had moderate to severe atopic eczema, at least one close relative with
allergies, and allergic sensitisation to pollen or house-dust mite, as shown by skin-prick tests (see p. 91).
The cetirizine was taken at fairly low doses and had no bad effects on the children in this study. What is more, it seemed to benefit their skin as well as reducing the risk of
asthma: those taking the drug had less need of high-strength steroid creams. There is some controversy about the validity of these results, so few children with atopic eczema
are receiving antihistamines at present.
No one yet knows if other antihistamines might have the same effect as claimed for cetirizine. Ketotifen, which is an atypical antihistamine (see p. 159), may do so.
Immunotherapy may also have a protective effect. One study, involving children suffering from nasal allergies, found that those given immunotherapy were less likely to develop
asthma (see p. 165). Another study shows that immunotherapy for children with mite allergy halves the risk of their developing new allergic reactions to other allergens.