PURPOSE OF THE STUDY.
To assess the outcome of oral food challenges (OFCs) in a pediatric patient population placed on elimination diets often based solely on the results of food-specific immunoassays (specific immunoglobulin E [IgE] testing).
Included was a pediatric population of 125 children (median age: 4 years) with active atopic dermatitis (AD) and food avoidance evaluated at National Jewish Health (Denver, CO).
This was a retrospective chart review of patients who underwent at least 1 OFC to evaluate for an IgE-mediated reaction. OFCs were conducted after reviewing clinical history, skin-prick-test (SPT) results, and serum allergen-specific IgE test results. If there was a history of a convincing reaction within the previous 6 to 12 months or if a reaction was life-threatening, then an OFC was not performed.
Ninety-six percent of the patients evaluated had AD, and OFCs were only undertaken once appropriate AD treatment had been started. Of the 364 OFCs performed on avoided foods, results were negative for 325 (89%). Of the 122 foods that were being avoided because of previous adverse reactions, 102 (84%) had a negative OFC result. Of the 111 foods being avoided because of immunoassay or skin-prick testing results, 103 (93%) had a negative OFC result. For foods without established decision points (ie, foods other than milk, egg, and peanut), there was a wide range of immunoassay results, and 93% had negative OFC results. Many foods were being avoided for reasons other than serum test results or a history linking the food to an observed reaction, and of those 131 OFCs, results were positive for only 11 of them.
Using serum food-specific IgE testing alone to diagnose food allergy, especially for children with AD, might result in an overly restrictive food-elimination diet.
Although the retrospective design of the study did cause some limitations, the takeaway point for pediatricians and allergists alike should be that SPTs and immunoassays alone do not definitively diagnose food allergy, especially when evaluating nonanaphylactic symptoms of food allergy (eg, AD). Serum allergen-specific IgE testing, when necessary, should be directed toward relevant allergens only. OFCs performed in a board-certified allergist's office to confirm food-allergy status remain the most reliable test for food-allergy diagnosis. Further prospective studies that examine specific IgE levels and SPT results for suspected food allergy in patients with and without AD are needed.
- Copyright © 2011 by the American Academy of Pediatrics