Atopic dermatitis at preschool age and contact allergy in adolescence: a population-based cohort study.

BACKGROUND: Atopic dermatitis (AD) is characterized by an impaired skin barrier, which can allow enhanced penetration of allergens. It is not clear whether AD influences the risk of developing contact allergy. OBJECTIVES: To examine the association between AD at preschool age and contact allergy at 16 years of age. METHODS: At 16 years of age, 2215 adolescents from the population-based cohort BAMSE were included. These adolescents had been followed with repeated questionnaires regarding AD throughout childhood, and contact allergy was assessed by skin patch test at 16 years. RESULTS: AD at preschool age was associated with contact allergy to at least one of the tested substances at 16 years of age among boys [adjusted odds ratio (OR) 1·51, 95% confidence interval (CI) 1·03-2·20] but not among girls (adjusted OR 0·77, 95% CI 0·54-1·10). AD at preschool age was not associated with contact allergy to nickel in either boys or girls. In contrast, AD at preschool age was associated with contact allergy to fragrance mix I (adjusted OR 3·10, 95% CI 1·66-5·80). This association was observed especially for AD at preschool age in combination with IgE sensitization to airborne or food allergens (adjusted OR 3·80, 95% CI 1·67-8·61). CONCLUSIONS: The results suggest that AD in early childhood may be associated with contact allergy to fragrances, but not to nickel, in adolescence.