Background: Hen’s egg is one of the main causes of food allergy in children. Accidental exposure is common in food-allergic patients. However, the few studies that analyze this problem focus mainly on peanut allergy. We sought to calculate the frequency of accidental exposure reactions in children allergic to hen’s egg during a 12-month period, to analyze the clinical characteristics and circumstances surrounding the reactions, and to identify risk factors for the most severe reactions.

Methods: Ninety-two egg-allergic children (55 boys; median age, 52 months) were included in the study. A systematic questionnaire about accidental exposure was administered. Reactions were classified as mild, moderate, and severe. Egg white–specific immunoglobulin (Ig) E antibody titers were determined.

Results: Nineteen (21%) children had 24 reactions in the previous year (42% mild, 50% moderate, and 8% severe). Most reactions took place at home (50%) under routine circumstances (83%). Children with severe or moderate reactions had higher specific IgE levels to egg white (adjusted odds ratio for every 0.1-unit increase in the decimal logarithm, 1.15; 95% CI, 1.03-1.28; P=.008) and lower serum total IgE (adjusted odds ratio for every 1-unit increase in the decimal logarithm, 0.16; 95% CI, 0.05-0.54; P=.001) than those children with mild or no reactions.

Conclusions: Reactions to accidental exposure are frequent in children with egg allergy. The proportion of severe or moderate reactions was 58%. The risk factors for such reactions included high titers of specifi c IgE to egg white and low titers of serum total IgE.

Key words: Egg allergy. Accidental exposure. Accidental ingestion.