BACKGROUND: Case reports suggest that children with food-triggered atopic dermatitis (AD) on elimination diets may develop immediate reactions on accidental ingestion or reintroduction of an avoided food. OBJECTIVE: The objective of this study was to systematically study the incidence and risk factors associated with these immediate reactions. METHODS: A retrospective chart review of 298 patients presenting to a tertiary-care allergy-immunology clinic based on concern for food-triggered AD was performed. Data regarding triggering foods, laboratory testing, and clinical reactions were collected prospectively from the initial visit. Food-triggered AD was diagnosed by an allergist-immunologist with clinical evaluation and laboratory testing. We identified immediate reactions as any reaction to a food for which there was evidence of sIgE and for which patients developed timely allergic signs and symptoms. Differences between children with and without new immediate reactions were determined by a Mann-Whitney, chi(2), or Fisher's exact test as appropriate. RESULTS: A total of 19% of patients with food-triggered AD and no previous history of immediate reactions developed new immediate food reactions after initiation of an elimination diet. Seventy percent of reactions were cutaneous but 30% were anaphylaxis. Cow's milk and egg were the most common foods causing immediate-type reactions. Avoidance of a food was associated with increased risk of developing immediate reactions to that food (P < .01). Risk was not related to specific IgE level nor a specific food. CONCLUSION: A significant number of patients with food-triggered AD may develop immediate-type reactions. Strict elimination diets need to be thoughtfully prescribed as they may lead to decreased oral tolerance.