[Historical aspects concerning the symptom of itch in the German-speaking region (1850-1939)].

Since the establishment of dermatology as an independent discipline of medicine in the middle of the 19th century, pruritus or itch has been a subject of research. The goals were to discover the etiology of pruritus, to develop useful therapies and to achieve a classification within the system of skin diseases. Looking at historical aspects of pruritus demonstrates just how difficult it has been to approach this problem. The difficulties even influence present day pruritus research. For example, there is no definite international standard of pruritus. Etiology-oriented classifications have dominated, but have recently been supplemented by a clinical classification.