The atopic eczema/dermatitis syndrome. Epidemiology, natural course, and immunology of the IgE-associated ("extrinsic") and the nonallergic ("intrinsic") AEDS

Abstract

According to the position paper from the EAACI nomenclature task force, the term "Atopic eczema/dermatitis syndrome" (AEDS) should be used as the "umbrella" term to cover the different subtypes of atopic dermatitis (AD). The new nomenclature (AEDS) underlines the fact that AD is not one, single disease, but rather an aggregation of several diseases with certain clinical characteristics in common. The so-called "intrinsic" type of AD (now termed nonallergic AEDS) fulfills the most commonly used diagnostic criteria for AD. These patients have no associated respiratory diseases, such as bronchial asthma or allergic rhinitis, show normal total serum IgE levels, no specific IgE, and negative skin-prick tests to aeroallergens or foods. Immunologic differences between the IgE-associated type of AD and the nonallergic type can be found in the cell and cytokine pattern in peripheral blood and in the affected skin, and also by phenotyping characterization of epidermal dendritic cells. The current explanation of this distinction is based on differences in genetics and/or environmental conditions. The classification into an allergic, IgE-associated (AAEDS) and a nonallergic type (NAAEDS) at each stage of life, i.e., infancy, childhood, teenage, and adult, is essential for the allergological management of patients as to allergen avoidance, secondary allergy prevention, and immunotherapy. The risk of an "atopy march" is significantly lower in children with the non-IgE-associated type.