Their study, reported in the November issue of the Journal of Allergy and Clinical Immunology, also found that clinicians can use blood levels of tree nut antibody (TN-IgE) as an accurate guideline in estimating the likelihood that a child has outgrown the allergy.

"What's crystal clear is that children with these allergies should be regularly re-evaluated," researchers concluded.

"Allergic reactions to tree nuts as well as peanuts (which are not nuts but legumes) can be quite severe, and they are generally thought to be lifelong," says senior author Robert Wood, M.D., director of the Division of Allergy and Immunology at the Children's Center. "Our research shows that for some children, however, lifelong avoidance of these nuts, found in countless food products, may not be necessary."

In the United States, an estimated one to two percent of the population is allergic to tree nuts (almonds, pecans, walnuts, cashews, Brazil nuts, hazelnuts, pine nuts, pistachios and macadamia nuts), peanuts or both. Wood and colleagues previously reported that as many as 20 percent of children outgrow peanut allergy and recommended that allergists periodically retest their patients. The current study explored whether the same held true for tree nuts.

Wood and colleagues evaluated 278 children, ages 3 to 21 years old, with a known allergy to tree nuts. Nine percent passed oral food challenges, the standard test to prove a child has outgrown a food allergy. Fifty-eight percent of children with TN-IgE levels of 5 kilounits per liter or less also passed the challenge.

"These findings give allergists a safe guideline in deciding whether to advise their patients to continue avoiding tree n
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Contact: Staci Vernick
svernick@jhmi.edu
410-516-4958
Johns Hopkins Medical Institutions
8-Nov-2005