Association between severity of atopic eczema and degree of sensitization to aeroallergens in schoolchildren

Background: A subgroup of patients with atopic eczema exhibits aggravation through contact with aeroallergens. Little is known from population-based studies, however, about the association between the severity of eczematous skin disease and the degree of aeroallergen sensitization. Objective: We sought to investigate the relationship between IgE-mediated allergic sensitization to aeroallergens and severity of atopic eczema in schoolchildren. Methods: A nested case-control analysis on atopic eczema was performed on the basis of a cross-sectional study of 2201 East German schoolchildren aged 5 to 14 years. Atopic eczema and its severity was identified by dermatologic examination. Total and allergen-specific IgE antibodies to grass and birch pollen, Cladosporium herbarum, Dermatophagoides pteronyssinus, and cat epithelium in serum were determined, and additional information was obtained by means of standardized questionnaire. Results: The overall prevalence of actual atopic eczema was 2.5%. Thirty-seven percent of the children were sensitized to at least one allergen. Children with atopic eczema were significantly more often sensitized than those without skin disease (75.0% vs 36.3%; odds ratio, 5.27; 95% confidence interval, 2.54- 11.15). This was observed for each single allergen. The prevalence of atopic eczema increased significantly with increasing RAST class (χ² trend test for each allergen, P < .0001). Also, the prevalence of sensitization increased with the severity of the disease (χ² trend test for each allergen, P < .0001). This association was pronounced for house dust mite and cat allergen. Multiple linear regression analyses showed significant associations between the severity score of atopic eczema and concentrations of allergen-specific IgE to dust mite (P = .032) and cat (P = .014) allergens after adjustment for sex, age, location, and parental predisposition. Conclusions: The degree of sensitization is directly associated with the severity of atopic eczema. We speculate that early epicutaneous sensitization to aeroallergens may be enhanced by damage of the skin barrier function. The specific IgE response seems to contribute to the severity of the disease in a dose-dependent fashion.