Will a child outgrow an allergy?

Here we concentrate on immediate-onset food allergy, where symptoms usually appear within seconds or minutes of contact with the food.

Most children with a food allergy outgrow their allergy during childhood. This is particularly true for allergy to cow’s milk, wheat and hen’s eggs. For a few children, allergies to any of these foods can persist.

Some food allergies are less likely to be outgrown, particularly for allergies to peanuts, tree nuts (such as walnuts, cashews and Brazil nuts), fish and shellfish. With day-to-day management, risks can be greatly reduced. Find more information on all these allergies below.

A systematic review of all the published studies from 2020 found that between 9-14% of children with tree nut allergy outgrew this allergy. This included some children who had had severe reactions.

The age by which the children outgrew both peanut and tree nut allergies varied significantly, so it is important for your child to have regular reviews with their allergy specialist.

Read more about tree nut allergy.

The prognosis for outgrowing a milk allergy is very positive, but research does suggest that the age this happens at varies.  In the last 10 years, there has been a shift towards tolerating milk at a later age.

In the CoFAR and Europrevall studies, 53% of children outgrew their allergy by two years of age, and 57% outgrew their allergy at one year. However, as with the egg allergy, some studies have shown a slower rate of achieving tolerance, with one reporting that 19% outgrew their cow’s milk allergy at age 4, 42% at age 8, 64% at age 12, and 79% at age 16.

True wheat allergy happens when the body’s immune system reacts to one or more of the proteins found in wheat. Only a limited number of studies have looked at when wheat allergy is outgrown. A study from 2017 found that 45% of children outgrew their wheat allergy by five years of age.

Read more about wheat allergy.

As children can outgrow their allergy, it is important to have regular follow-up appointments with your allergy specialist. If you believe your child may have outgrown their food allergy and have no appointment planned, seek medical advice. Your GP can refer you to an allergy clinic where your child may be given an oral challenge to check whether they have outgrown their allergy. Such challenge testing involves the child eating small amounts of the food, gradually building up the quantity until it can be shown that they are not allergic. This must be strictly controlled at an allergy clinic and should not be tried at home.

If the test is negative, this means your child is no longer allergic. There is a very strong chance that the allergy will not come back, although this does happen in a very small number of cases. If your child has been carrying adrenaline, the question of whether they should play safe and still carry adrenaline must be discussed with the doctor overseeing the challenge. Some doctors advise that injectors should continue to be carried for a further limited period.

Finally, if your child has outgrown their food allergy, you may wonder if they should eat the food or avoid it. There is strong evidence that you should include the food regularly in your child’s diet to ensure the tolerance to the food is maintained, and this view is widely supported by the medical community. If your child does not like the food, it is advisable to discuss this with your child’s dietitian to find foods your child likes that contain the allergen.