Atopic dermatitis and asthma.

Atopic dermatitis (AD), a chronic inflammatory skin disease, frequently associated with respiratory allergy, is one of the most common skin disorders observed in children. The prevalence of AD and other allergic diseases is increasing in industrialized countries, representing a major burden on health care cost. AD has been proposed as an "entry point" for subsequent allergic diseases, suggesting the possibility that effective management of AD could prevent the development of respiratory allergy or at least reduce the severity of asthma and allergic rhinitis. AD and asthma share a common genetic and pathogenic basis, and several longitudinal studies provided evidence for the atopic march from AD to allergic rhinitis and asthma. However, because only a few prospective studies starting at children's births and having a sufficiently long follow-up have been developed, little is known about the natural course of AD and the potential succession of atopic phenotypes in childhood. Finally, recent genetic and epidemiological data raised the question whether AD may either develop to asthma or be part of a syndrome consisting of both diseases.