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Allergy Prevention in Children

Allergic disorders are often lifelong and although treatable, there is currently no cure.
It therefore makes sense to try to prevent allergic diseases in children, if possible.

Allergies are very common in children

Up to 40% of children in Australia and New Zealand are affected by allergic disorders some time during life, with 20% having current symptoms. Allergic diseases have approximately doubled in Western Countries over the last 25 years. The most common allergic conditions in children are food allergies, eczema, asthma and allergic rhinitis (hay fever). They are caused by immune system responses to otherwise harmless substances in our environment, such as pollen or house dust mites.

Symptoms range from mild to potentially life-threatening

Allergic diseases are caused by abnormal immune responses to otherwise harmless substances in the environment. For example, hay fever is commonly caused by an immune response in the nose and eyes to grass pollens and/or house dust mites. Some allergic conditions (such as mild hay fever) may cause only mild symptoms. For others (such as moderate/severe rhinitis, asthma), symptoms can be debilitating, disturb sleep and impact on learning and behaviour. Poorly controlled bad asthma, stinging insect allergy or severe food allergies can even be life threatening.

Why and how should we prevent children from developing allergic diseases?

Although effective treatments are available, there are currently no cures for allergic conditions. Therefore it makes sense to try to prevent these conditions, if possible, in infants and children.

Allergy prevention in infants and children is an active area of research but so far, we only have some answers. Recent research has identified some "risk factors" that appear to increase the risk of developing allergic disease. Other studies are examining whether avoiding these factors will reduce the risk.

At present the optimal approach to prevent children from developing allergies is to:

1. Identify infants that have an increased risk of developing allergic disease; and

2. Practise allergy prevention in the children who are identified as being at high risk of developing allergic disease.

Which infants are at risk of developing allergic diseases?

A number of factors appear to increase the risk of developing allergic disorders. We have no control over some risk factors such as family history, whilst there are other environmental factors that we might be able to influence. Identified risk factors for developing allergic disease include:

Family history of allergic disease in a parent or sibling (family history of allergic disease in both parents OR a parent and a sibling is associated with a further increased risk)
Introduction of cow's milk or soy milk formula before six months of age (a risk for eczema and food allergy)
Introduction of solid foods before 6 months of age (a risk for eczema and food allergy)
Birth in Spring (a risk for seasonal hay fever)
Passive exposure to cigarette smoke (a risk for increased respiratory symptoms)
There is some evidence to suggest that exposure to allergens such as house dust mite and food allergens in the first 6 months of life may increase the risk of developing asthma, however this remains controversial.

Practical suggestions for preventing allergic conditions in children

If your child is identified as being at increased risk of developing allergic disease, it is sensible to try to reduce the risk by following the recommendations outlined below.
It should be emphasised that even if you follow these suggestions, there is still a chance that a child at high risk may develop allergic disease, and that taking measures to reduce one type of allergy such as eczema, may have no effect on whether the child develops asthma or hay fever.

Do not smoke in the presence of the child, or in enclosed spaces where the child sleeps or plays.
Do not smoke during pregnancy.
Where possible, breast feed your child for the first 4-6 months. Breastfeeding provides a nutritious and balanced food source for your baby, reduces the risk of gastrointestinal tract infections and may also prevent the development of allergic diseases.
Where possible, delay the introduction of formula feeds until the child is 4-6 months of age.
If it is not possible to beast feed, use a partially hydrolysed (hypo-allergenic) cow's milk formula in the first 4-6 months of life, like Nan-HA or Karicare HA. It is important to note that if your child already has cows milk allergy, then these formulae will cause problems and should not be used. Ask your health professional for more information.
Delay the introduction of solid foods until the child is 4-6 months of age.
You may consider taking measures to reduce the amount of house dust mite exposure for the child (such as the use of mattress and pillow encasings which are impermeable to house dust mites and weekly hot washing of bedding).
It is currently unclear whether delayed introduction of allergenic foods like egg, milk, peanut, tree nuts, or seafood beyond the first 6 months of life reduces the risk of food allergy and eczema, but this advice is commonly given.

Research into allergy prevention is important

Although allergy prevention in children is an active area of research, our understanding of why allergic diseases develop and why they are increasing in our society is incomplete. We therefore encourage you to support and participate in studies on the development and prevention of allergic disease.

Some common questions regarding allergy prevention in infants and children

1. Will altering my diet during pregnancy prevent my child from developing allergic diseases?
Studies excluding "allergenic foods" (such as peanut, egg, fish, soy, cows milk) from the pregnant mother's diet have not been shown to reduce the risk of developing allergic diseases and have been associated with impaired weight gain by babies. Restricted diets during pregnancy are not recommended.

2. Will altering my diet while I'm breastfeeding prevent my child from developing allergic diseases?
Studies have failed to show that removing allergenic foods (see above) from a mother's diet while breast-feeding reduces the risk of their child developing allergies. Restricted diets during breast feeding are not recommended.

3. Are there any foods I should avoid feeding my child when solids are introduced?
The introduction of solid foods should be delayed until at least 4-6 months of age. Studies have shown that high risk children who were not exposed to cows milk, egg, peanut, fish or beef for the first 6 months of life were less likely to develop food allergies and eczema during the first 2 years of life. These restrictions had no impact on whether other allergic conditions developed (such as asthma, hay fever) or on the development of allergies in older children. These diets are very difficult to follow, and the benefits are only shown for the first 2 years of life.

* Any dietary restrictions or modifications should be discussed and supervised by your Doctor, who may also recommend a dietitian.

4. Is soy milk formula better at preventing allergies in my child than cows milk formula?
No. Studies have shown that the use of soy milk (or goats milk) formula does not prevent the development of allergies in children.

5. If I can't breastfeed, which formula is useful in preventing allergies?
Partially hydrolysed formula (such as NAN HA) or hypoallergenic (extensively or fully hydrolysed) formula (such as Alfare**, Neocate**, Pepti-Junior**, Elecare**) are cows milk based formula that has been processed to break down most of the proteins which cause symptoms in infants who are allergic to cows milk. Studies have shown that using hydrolysed formula instead of conventional formula in high risk infants reduces the risk of developing eczema and cows milk allergy in infancy and early childhood.

In Australia and New Zealand hypoallergenic formula is only available on prescription and most often used to treat children with established cows milk allergy. The high cost of hypoallergenic formula is subsidised by the Pharmaceutical Benefits Scheme in Australia (and by Pharmac in New Zealand) only when there is proven food allergy in infants, and even then only under restricted circumstances.
Partially hydrolysed formula is usually available without prescription at pharmacies and can be used for the purposes of prevention of allergic disease in high risk infants, but is not appropriate if cows milk allergy already exists.

6. Should I avoid pets?
There is no reason to remove pets from the household unless a person is already allergic to them.

7. Will taking fish oils prevent allergy?
There is no convincing evidence at this time that taking fish oil supplements during pregnancy have any significant benefit.

8. Are probiotics useful in preventing allergies?
There are conflicting studies on the benefit of giving probiotics for the prevention of allergic disease. Two studies have shown that probiotic supplements taken in late pregnancy by the mother, and to the baby in the first 6 months of life, protected against the development of eczema. Another study, however, showed that giving a different probiotic supplement only to the baby in the first 6 months of life had no effect on the development of allergic diseases. Probiotics are not currently recommended for preventing allergies but this area is under further study.

9. Will immunotherapy ("desensitisation") prevent allergy?
The current role of immunotherapy is to treat established allergies. However, there is preliminary evidence that treating children who have hay fever with immunotherapy to "switch off" allergy may reduce the risk of them developing later asthma or new sensitivities. This is an area of active research.

Disclaimer

The content of this article has been reviewed by ASCIA members, represents the available published literature at the time of review and is not intended to replace professional medical advice. Any questions regarding a medical diagnosis or treatment should be directed to a medical practitioner.

For further information on allergy, asthma or immune diseases,
visit http://www.allergy.org.au/ - the web site of
ASCIA is the peak professional body of Clinical Allergists and
Immunologists in Australia and New Zealand.

Contact details
PO Box 450 Balgowlah NSW Australia 2093
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© ASCIA 2007
This article was last updated in June 2007.

ALLERGY PREVENTION IN CHILDREN - SUMMARY

BEFORE PREGNANCY
Stop smoking	Yes

DURING PREGNANCY
Stop smoking	Yes
Probiotics	No	Await further research studies
Dietary Restrictions	No
Fish oil supplements	No

NEWBORN BABIES

FEEDING
Breast-feeding	Yes	Exclusively 4-6 months if possible
Partial breast-feeding		Supplement with a partially hydrolysed cows milk formula such as NAN HA or Karicare HA (unless infant is already cows milk allergic)
Soy formula		Only if allergic to cows milk but not allergic to soy
Weaning		Avoid introduction of solids until aged 6 months

ALLERGEN AVOIDANCE
Diet restrictions	No	Await further research studies
Removal of pets	No	Only if family member is already allergic to pets
Dust mite avoidance	Maybe	Avoidance measures may be considered

AVOID ENVIRONMENTAL IRRITANTS	Yes	Avoid exposure to tobacco smoke, unflued indoor gas heaters, remove sources of mould and dampness where possible

LATER CHILDHOOD
Immunotherapy	No	Useful to treat established allergies - await further studies regarding its role in prevention