Clinical aspects and differential diagnosis of atopic dermatitis

Atopic dermatitis (AD) is a pruritic, chronic, relapsing condition that usually begins in early infancy or childhood. Onset in adulthood is much less common but is reported to be as high as 13.6% in a study from Singapore and 24.5% in Nigeria (Tay et al. 1999, Bannister and Freeman 2000, Nnoruka 2004). The term ‘atopic dermatitis,’ introduced by Wise and Sulzberger (1933), incorporated infantile eczema and so-called generalized neurodermatitis into one clinical syndrome and emphasized the association with allergic rhinitis and asthma, and the presence of the immunoglobulin IgE. There is an active debate over the classification of AD because a minority of cases lack seasonal rhinitis, asthma, and allergen-specific IgE. The AD clinical phenotype described herein is that proposed by Wise and Sulzberger (1933) and later by Hanifin and Rajka (1980). The term ‘atopic dermatitis’ is used to include both so-called extrinsic atopic dermatitis and intrinsic (atopiform) dermatitis/eczema (Bos 2002).