Is atopic dermatitis always associated with an altered epidermal barrier function?

The principal function of the epidermis, the establishment of a multifunctional barrier between the body and its external environment, is mainly provided by the stratum corneum. One of the clinical characteristics of atopic dermatitis is an increase in the permeability of the epidermis. Other alterations of the stratum corneum have been described. The discovery that mutations in some genes essential for the epidermal barrier may be predisposing factors for the disease, including the filaggrin gene, shows that such epidermal defects are not secondary to inflammation alone, but may also be considered as etiological factors. Such defects allow penetration of allergens into the skin through the stratum corneum. (C) 2013 Elsevier Masson SAS. All rights reserved.