Atopic dermatitis is associated with a fivefold increased risk of polysensitisation in children.

Aim: It has been hypothesised that in atopic dermatitis, the dysfunctional skin barrier facilitates the transcutaneous presentation of allergens to the immune system. This study examined whether atopic dermatitis increased the likelihood of polysensitisation, namely sensitisation to five or more allergens.

Methods: We examined the electronic hospital charts of 1743 children aged 0-17 years who had visited primary or secondary care physicians with allergic symptoms, whose blood was examined for the presence of specific immunoglobulin E (IgE) to the 10 most common inhaled and food allergens and whose files contained documentation of the presence of atopic dermatitis and other skin disorders. Sensitisation was defined as a specific IgE level of ≥0.35 kU/L.

Results: Polysensitisation was more common in children with atopic dermatitis (268/1197, 22.4%) than those without (30/546, 5.5%, p < 0.001). This remained significant after adjustment for gender and age in a multiple logistic regression model (odds ratio: 5.63, 95% confidence interval 3.77-8.40). Other skin disorders did not show an increased risk of polysensitisation (5/97, 5.2%).

Conclusion: Polysensitisation was considerably more common in children with atopic dermatitis than those without. This supports the hypothesis that sensitisation occurs through a defective skin barrier and appears to be specific for atopic dermatitis.