ABSTRACT
Eczema is divided into endogenous and exogenous types. In the latter, identifiable external substances (allergens and irritants) induce the eczema at the site of contact of the substance. In endogenous eczema, the disease is essentially due to constitutional factors but the exact pathogenetic mechanisms have yet to be elucidated. The classification of endogenous eczema is based on the clinical patterns of the disease. Apart from atopic eczema, the other patterns of endogenous eczemas are seborrheic (infantile and adult forms), discoid or nummular, hand and foot (pompholyx), hypostatic and asteatotic. These clinical patterns are not always distinct, and often there may be combined features of two or even three patterns. In addition, an individual with one pattern of endogenous eczema is more likely to develop another at a different time or in combination.
