Outgrowing food allergies

A common question parents ask is: How likely is it that my children will outgrow his or her food allergy? The answer to that question differs for various foods.  Most children allergic to cow's milk, egg, soy and wheat will outgrow their allergy between the ages of 3 and 16 years of age.

The prognosis for peanuts and tree nuts is much different. Clinicians used to believe that peanut allergy is life-long, but more recent studies show that 20% of peanut-allergic children outgrow the allergy.  Less than 10% of children outgrow allergy to tree nuts (walnuts, cashews, almonds, pistachios, etc).

Food challenges

Unless a child has a history of a severe reaction, most food challenges are done in the outpatient clinic. The child must be in good health and off antihistamines prior to the challenge. Your medical provider will discuss the procedure with you and obtain informed consent prior to starting the procedure. For safety reasons, a physician is always present, and emergency medications are immediately available.

In an oral food challenge, the child eats gradually increasing quantities of the food until they have consumed a full serving. Typically this part of the procedure is completed within 60 minutes. The child is examined and vital signs are checked before each small portion of the food consumed. After the child has eaten the full serving, he or she is monitored for an additional two hours before being allowed to go home.

Risks for redeveloping peanut allergy

Children at increased risk for redeveloping peanut allergy were those who ate peanut products in limited, infrequent amounts after passing the challenge. We recommend that children who have outgrown their peanut allergy eat a full serving of a peanut product at least once a month. Those who eat peanut only infrequently or in small amounts should continue to carry auto-injectable epinephrine.

Risks involving tree nuts

Tree nuts include almonds, walnuts, cashews, hazelnuts, pecans, pine nuts, and pistachios. A study published in 2005 looked at 278 people between the ages of 3 and 21 (mostly children) with tree nut allergy. This study found that 9% of them outgrew their allergy, even if they had a history of previous severe reactions to tree nuts and previously failed an oral challenge to the same nut.

What does this mean to the parent of a food-allergic child?

We recommend evaluations on a yearly basis with an allergist experienced in food allergy. These assessments should include follow-up testing. In the allergy program at Children's Memorial, a blood test called ImmunoCAP® is done to measure the level of IgE to a particular food. Declining levels may indicate that tolerance is developing. Depending upon the child's prior reactions, a physician-supervised oral food challenge may be recommended. A supervised oral food challenge is the safest way to confirm whether or not a child has outgrown food allergy. If a child passes the challenge without any problems, he or she may begin eating full servings of the food.