Zum Wandel des Ekzem-Begriffes: Klassisches versus atopisches Ekzem

The history of the terminology of eczema dates back 2000 years ago and is full of controversies. Today we define eczema as 'non-contagious epidermo-dermitis with typical clinical (erythema, papule, vesicle, squames, crusts, lichenification in the sense of synchronous or metachronous polymorphia) and dermato-histological (spongiosis, akanthosis, parakeratosis, lymphocytic infiltration) morphology mostly on the basis of individual hypersensitivity'. The most frequent forms of eczema are atopic eczema and contact eczema. Unfortunately, however, the term contact eczema only describes the route of elicitation and not the real difference from atopic eczema which also can be elicited by exogenous contact. The old term 'eczema vulgare' does not seem suitable for modern diagnosis. Therefore we propose the term 'classic eczema' versus 'atopic eczema'. Both can be elicited systemically as well as by external contact. Both can be induced by allergic (extrinsic) or non-allergic (kryptogenic or irritative-toxic) mechanisms. The most relevant difference pathophysiologically is the involvement of TH2 cells and IgE antibodies in atopic eczema, while allergic classic eczema is mediated by TH1-Cells. A third group of 'other eczemas' may include seborrhoic eczema, nummular eczema and other forms of unclassified eczemata which are pathophysiologically not so well defined as to allow rational classification. This classification gives room for further research and solves the decade-old dilemma of misunderstanding the two most frequent forms of eczema.