How Do You Know if an Allergy is Truly Gone?

Published: September 20, 2013

Q: My 6-year-old daughter’s IgE blood test numbers for peanut allergy have significantly decreased, and the allergist is offering an oral challenge test. My question: as allergic reactions aren’t consistent, if she doesn’t react or has only minor symptoms on the day of the oral challenge, can we be certain this allergy is truly gone? Would you continue to carry epinephrine, at least for a while?

Dr. Sicherer: For most foods, when tolerance to a food is proven during a doctor-supervised feeding test using a meal-sized portion or more without symptoms, it is uncommon to experience a return of the allergy. The rate of recurrence has been higher with peanut. While about one in five children will resolve their peanut allergy, between 5 and 10 percent later experience a recurrence.

It’s important to note that the children whose peanut allergy resurfaced generally are those who avoided peanut for a prolonged time following their oral food challenge, or they only consumed products with trace amounts, and then experienced symptoms when concentrated peanut (peanuts, peanut butter) was finally eaten. The children with recurrence usually had not had concentrated peanut products for a year or more following the food challenge.

In contrast, children without recurrence of their allergy were generally eating concentrated peanut at least monthly. While it may be that the children whose allergy resurfaced were having subtle symptoms making them want to avoid peanut, another explanation could well be that continuing to consume peanut after the allergy has resolved prevents the immune system from going back to an allergic state.

Before undertaking an oral food challenge, discuss with your allergist whether your child is likely to incorporate peanut into the diet. If peanut is tolerated, routine consumption is encouraged. If your child refuses to eat peanut for a prolonged period, retesting and possibly a repeat food challenge may be needed.

Because there is a small risk of recurrence, your allergist may recommend continuing to carry epinephrine for a period of time after a successful food challenge. The decision to stop carrying it will depend upon factors such as the length of time that peanut has been eaten without symptoms and the quantities that are being consumed.

Dr. Scott Sicherer is a practicing allergist, clinical researcher and professor of pediatrics. He is Chief of the Division of Allergy and Immunology, Jaffe Food Allergy Institute, at the Icahn School of Medicine at Mount Sinai in New York. He’s also the author of Food Allergies: A Complete Guide for Eating When Your Life Depends On It.

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