Role of immediate food hypersensitivity in the pathogenesis of atopic dermatitis.

Twenty-six children with atopic dermatitis and markedly elevated serum IgE concentrations were evaluated for clinical evidence of hypersensitivity to foods with double-blind placebo-controlled food challenges. Selection of foods for challenges was based on positive prick skin tests (greater than 3 mm wheal) or a convincing history. At least one positive skin test to a food antigen was found in 24/26 patients. A total of 111 double-blind placebo-controlled challenges were performed in these children after suspect foods were eliminated from their diets for 10 to 14 days. There were 23 positive challenges in 15 children, 21 of which manifested as cutaneous symptoms, primarily pruritus and an erythematous macular and/or maculopapular rash involving 5% (or greater) of the body surface. In all, 14 children (54%) developed cutaneous symptoms after food challenges. All symptoms occurred within 10 min to 2 hr of challenge; nasal symptoms, mild wheezing, and gastrointestinal symptoms were seen in some children. No symptoms occurred in 104 placebo challenges. There were 86/111 clinically insignificant positive skin tests (77%) and three false-negative skin tests. These studies demonstrate that in some children with atopic dermatitis, immediate food hypersensitivity can provoke cutaneous pruritus and erythema, which leads to scratching and subsequent eczematoid lesions.