Parents often ask if it is likely that their child will outgrow a food allergy. The answer differs for various foods. Most children allergic to cow's milk, egg, soy and wheat will outgrow their allergy between 3 and 16 years of age. The prognosis for peanuts and tree nuts is much different. Clinicians previously believed that a 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.
Unless your child has a history of a severe reaction, often we can use a food challenge test in the outpatient clinic. Your child must be in good health and off antihistamines prior to the challenge. Your physician will discuss the procedure with you and obtain informed consent before 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 segment 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 they have eaten a full serving, they are monitored for an additional two hours before leaving the outpatient clinic.
Risks for Redeveloping a Peanut Allergy
Children who eat peanut products in limited, infrequent amounts after passing the challenge are at increased risk for redeveloping a peanut allergy. 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 products infrequently or in small amounts should continue to carry auto-injectable epinephrine.
Risks with Tree Nuts
Tree nuts include almonds, walnuts, cashews, hazelnuts, pecans, pine nuts and pistachios. A study published in 2005 found that 9% of participants 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.
We recommend evaluations and follow-up testing on a yearly basis with an allergist experienced in food allergy. In our Food Allergy Program, a blood test is used to measure the level of IgE to a particular food. Declining levels may indicate that tolerance is developing. Depending upon your child's prior reactions, a physician-supervised oral food challenge may be recommended. A supervised oral food challenge is the safest way to confirm if your child has outgrown their food allergy. If they pass the challenge without any problems, they may begin eating full servings of the food.