Egg allergy in infancy predicts respiratory allergic disease by 4 years of age.

Sensitization to hen's egg early in life has been proposed as a predictor for respiratory allergic disease during childhood. However, symptomatic egg allergy in infancy has not been studied in this context. In 1989, a cohort of consecutive births was recruited. Data on family history of atopy and environmental factors were collected. At 4 years of age, 1,218 children were seen of whom 981 were skin-prick tested with a range of food and aero-allergens. Of the 1,218 children, 29 (2.4%) had suffered symptomatic egg allergy (20 during infancy). Egg allergy in infancy was associated with increased respiratory (asthma, rhinitis) allergic disease (odds ratio [OR] 5.0, 95% confidence intervals [CI] 1.1-22.3; p < 0.05) at 4 years of age, with a positive predictive value (PPV) of 55.0%. The addition of infantile eczema to egg allergy increased the PPV to 80% whereas the addition of family history of atopy had no effect. Egg allergy also increased aero-allergen sensitization (OR 6.1, CI 1.1-37.5; PPV 61.1%; p < 0.05). As a predictor for respiratory allergic disease and aeroallergen sensitization, it carried a high specificity but poor sensitivity. Hence, egg allergy in infancy, especially when coexisting with eczema, increases respiratory allergic symptoms and aero-allergen sensitization in early childhood.