Low prevalence of the intrinsic form of atopic dermatitis among adult patients

Background: Atopic dermatitis (AD) is a chronic inflammatory skin disease commonly associated with respiratory allergies such as rhinitis and asthma, and a high serum level of IgE. In contrast to the 'classic' IgE-mediated allergic (extrinsic) form of AD, approximately 20% of the patients are reported to show normal IgE levels, lack of sensitizations towards environmental allergens, and absence of associated respiratory allergies. Accordingly, these patients are assigned to a nonallergic (intrinsic) form of the disease. Objectives: In order to define these two forms of AD more closely, 259 adult patients with AD were investigated. Results: After a thorough diagnostic workup there were 18 patients (6.9%), who fulfilled the criteria of intrinsic AD. After follow-up, four additional patients had developed respiratory allergies or IgE-mediated sensitizations resulting in an overall proportion for intrinsic AD of 5.4%. Conclusions: Based on these figures the nature and relevance of the intrinsic form of AD deserves further evaluation.