[Eosinophilic dermatoses].

Morphological and functional properties of the eosinophilic granulocyte (e. G.) feature this haematopoietic stem cell-derived cell type as an important cellular component of defense mechanisms, immunologic reactions and proinflammatory/neoplastic processes. Over the last decade significant advances of the molecular pathophysiology of eosinophilic disorders enable increasingly the distinction between the more common reactive (secondary) and clonal eosinophilia including the hypereosinophilic syndrome. This review features a comprehensive clinical summary of dermatological disorders that are frequently associated with transient or persistent eosinophilia belonging to the reactive eosinophilia. The hypereosinophilic syndrome is a subset of idiopathic eosinophilia frequently associated with major tissue targets as skin, heart and others. Therefore, the hypereosinophilic syndrome has to be considered as important differential diagnosis. Most recently, the identification of selective targets (e. g. IL-5, CD52) has translated into therapeutic approaches with monoclonal antibodies such as mepolizumab, alemtuzumab or SCH55700.