Auckland Allergy & Eczema Clinic

Allergy Prevention

Allergy Prevention

Updated May 24, 2006

Preventing allergies in infancy is currently a major focus for allergy specialists and new information is emerging all the time. The following recommendations are based on the most up-to-date research and advice from allergy specialists internationally and nationally. They are now widely accepted as sensible, prudent measures to take if you have any allergies in your family.

What is an allergy?

An allergy occurs when the body's immune system over-reacts to normally harmless substances, which may be in the air or water, or things we touch or eat. When an allergic person comes in contact with such a substance their immune system produces a special kind of antibody (IgE) and other cells release further chemicals (histamines). This causes the symptoms of an allergic reaction.

What makes a baby susceptible to allergies?

Your baby may inherit the tendency to develop allergies, if you, your partner, or any of your family suffers from eczema, asthma, hayfever or hives, allergic rhinitis, persistent cough, constant runny nose, food allergies (especially allergy to dairy, eggs, wheat, soy, peanuts, nuts, fish and shellfish), or recurrent ear infections.

Even if neither parent is allergic, there is still a 5-15% chance of a child developing allergies. For a child with one allergic parent the risk goes up to 25%, and if both parents are affected, there is a 50-60% chance of developing allergies. When both parents have the same allergic disease the risk increases to as high as 80%. The first child in the family is more at risk.

What the child inherits is the tendency to develop an allergy or allergies, not the specific hypersensitivity of any family member to specific allergenic factors. For example, if a parent has an allergy to shellfish the child will inherit the chance of being allergic, but not the specific shellfish allergy. The infant is born with the capacity to become sensitised to some allergen at some time. The stronger the family history of allergy, the greater the risk and the earlier the infant is likely to show symptoms.

The likelihood that a child will develop an allergy depends on both genetic and environmental factors. Children must be exposed to a potential allergen to become sensitised. Once this sensitivity is established, it can take very little contact with the allergen to cause a reaction and the child is also at risk of becoming allergic to other allergens.

There are some simple but very important steps you can take to, either prevent the development of allergies or at least reduce the potential severity of reactions.

How can I prevent my child from developing allergies?

During pregnancy

Genetic factors are givens and out of your control. However, you do have some control over the exposure your baby has to allergens that can set off allergies in a child who is more likely to suffer from these conditions because of his or her genetic programming.
There is now good evidence that sensitisation to allergens occurs "in utero" or during pregnancy, and that it can start as early as 22 weeks.

There is also some evidence that reducing the number of times a women suffers from allergic reactions while she is pregnant can help reduce the chances of the baby becoming allergic. If a woman is reacting to allergens during pregnancy there is a high chance it will affect the baby and create a higher likelihood of the infant becoming allergic.

Prevention therefore starts in early pregnancy, and involves reducing your own exposure to allergens. This is done by:

  • Reducing allergens such as pets and house dust-mites and irritants such as cigarette smoke (which make allergies worse) in your home
  • Research in Allergy prevention is ongoing, and advice we give is constantly changing. The current advice is that highly allergenic foods like peanuts, nuts, milk, eggs & fish should not be excluded from your diet. But they probably should not be eaten in excess (cravings) either. The baby's immune system might need "normal" amount of these allergens to mature normally.

While breastfeeding

It is very clear that sensitisation continues during breastfeeding and that significant amounts of allergens pass through the breastmilk causing allergic symptoms in babies. Infants born into a family with a history of allergy should be breastfed exclusively, if possible, for a minimum of six months.

Several studies have shown that breastfeeding helps to reduce the odds of developing an allergy when compared to feeding with standard milk or soy based formulas. However, this advantage is dependent on your diet. The same issues and preventative measures apply as in pregnancy, but again it is important, that in avoiding allergens you don't compromise your own diet. If breastfeeding is not possible or if a supplement to breastmilk is desired, use a hypoallergenic formula (ask your allergy specialist for advice on this). Soy-based formula or goat's milk formula are not recommended for allergic or potentially allergic infants.

If your child develops eczema and you suspect that food allergens (milk, egg, peanuts) are being passed into your breast milk and aggravating the eczema, you should have your child skin prick tested, to find out which allergen you need to omit from your diet. 

When introducing solids

  • Care is needed when introducing food, because the earlier a child is exposed to allergens, the more likely they are to cause an allergic reaction. Ask for guidance from a registered dietitian and either your GP or an allergy specialist to ensure your baby gets all the important nutrients.
  • Where there is a family history of allergy, solids should not be introduced before six months if possible 
  • Start with the least allergenic foods first, such as baby rice, pears and yellow vegetables, introducing one new food per week. Begin with small amounts and increase gradually. All foods, even fruits, should be cooked 
  • At the age of eight to nine months you can start to give your child oats, green vegetables, and meats 
  • Delay the introduction of known allergens until the baby is older and hopefully more able to tolerate them 
  • Do not introduce wheat and soy until nine months (12 months to be cautious), cow's milk until 12 months, eggs until 18-24 months and peanuts, nuts, fish and shellfish until 36 months 
  • If there is a strong family history of allergy, also delay giving your child legumes, tomatoes, citrus fruit, ham, bacon and processed meats until after their first birthday and berry fruits, chocolate, spices, colourings and artificial flavourings until after their second birthday.

If your baby is at risk of developing an allergy, avoid using massage oil or nipple cream containing peanut oil, and make sure that the nappy rash products you use are also free from this ingredient. Using these products can sensitise your baby.

General precautions

Try to minimize the exposure to inhalant allergens as well, such as cigarette smoke, polluted air, strong odours, animal fur, feathers, and dust mites.

  • If you smoke, stop! There is strong scientific evidence that exposure to cigarette smoke can contribute to the development of asthma and allergic disease 
  • Don't get new pets, seriously consider giving ones you already have away, or at the very least, keep them outside, and don't let them in the car. Cat fur is the most allergenic, but other animal fluff, fur or feathers can also cause problems
  • Allergy to dust mites is one of the biggest causes of asthma in New Zealand. Research has demonstrated that lowering the exposure to dust-mite allergens helps to reduce the frequency and severity of symptoms. The major source of dust-mite allergen is the bedding (mattress, pillow and sheets). Use dust-mite bedding covers on your baby's bed right from birth
  • Soft toys should be washable and regularly put into hot water. Alternatively you can freeze them from time to time to eliminate the dust mites. Try to reduce soft toys around your baby and avoid older, long "loved" stuffed animals, because they could contain high amounts of dust-mite allergens which will be difficult to remove
  • Get rid of your carpets, if possible. Polished floors are the best solution. Curtains become very dusty and should be cleaned regularly. Keep furnishings to a minimum
  • Clean your house frequently and carefully. If you are considering buying a new vacuum cleaner, choose one with a HEPA filter, which absorbs a great amount of inhalant allergens without allowing these tiny allergic particles to escape back into the air
  • Avoid using sheepskin rugs and sheep wool fabrics for your infant.

What are the early warning signs of allergy?

Parents should look for early signs of sensitivity such as:

  • Colic (not exclusively caused by allergy but can be an allergic symptom), excessive vomiting, abdominal pain, diarrhoea or constipation
  • Skin rashes and eczema
  • Swelling or welts 
  • Persistent sniffling and wheezing, stuffy nose, frequent colds, recurring ear infections
  • An unexplained change of behaviour as well as difficulties in breastfeeding or refusal of food.