Eczema and dermatitis

Abstract

Eczema is an inflammatory skin disease which is characterized by itching and scaling plaques and patches on different skin sites. Histopathologically, a characteristic feature is the presence of epidermal edema or spongiosis. Eczema can develop at any age and may be associated with skin inflammation caused by irritation or allergy. Some forms of eczema have no apparent trigger although as our understanding of the molecular basis of skin disease grows, new pathways, such as the role of mutations in the filaggrin gene in atopic eczema, have been found to have a role in pathogenesis, in some individuals. This section will concentrate on two common forms of eczema, atopic dermatitis and contact dermatitis. It will also consider seborrhoeic dermatitis which, although not strictly speaking a form of eczema, shares some common features. This scaly inflammatory dermatosis is largely caused by an inflammatory response triggered by a member of the normal skin microbiome, the yeast Malassezia.