Utility of food-specific IgE concentrations in predicting symptomatic food allergy.

BACKGROUND: The double-blind, placebo-controlled food challenge is considered the gold standard for diagnosing food allergy. However, in a retrospective analysis of children and adolescents with atopic dermatitis and food allergy, discrete food-specific IgE concentrations were established that could predict clinical reactivity to egg, milk, peanut, and fish with greater than 95% certainty.

OBJECTIVE: The purpose of this investigation was to determine the utility of these 95% predictive decision points in a prospective evaluation of food allergy.

METHODS: Sera from 100 consecutive children and adolescents referred for evaluation of food allergy were analyzed for specific IgE antibodies to egg, milk, peanut, soy, wheat, and fish by using the Pharmacia CAP System FEIA. Food-specific IgE values were compared with history and the results of skin prick tests and food challenges to determine the efficacy of previously established 95% predictive decision points in identifying patients with increased probability of reacting during a specific food challenge.

RESULTS: One hundred children (62% male; median age, 3.8 years; range, 0.4-14.3 years) were evaluated for food allergy. The diagnosis of food allergy was established by means of history or oral food challenge. On the basis of the previously established 95% predictive decision points for egg, milk, peanut, and fish allergy, greater than 95% of food allergies diagnosed in this prospective study were correctly identified by quantifying serum food-specific IgE concentrations.

CONCLUSION: In a prospective study of children and adolescents referred for evaluation of food allergy, previously established 95% predictive decision points of food-specific IgE antibody concentrations for 4 major food allergens were effective in predicting clinical reactivity. Quantification of food-specific IgE is a useful test for diagnosing symptomatic allergy to egg, milk, peanut, and fish in the pediatric population and could eliminate the need to perform double-blind, placebo-controlled food challenges in a significant number of children.