1. Department of Dermatology, Venereology and Allergology; Ruhr University Bochum; D-44791 Bochum Germany
2. Department of Dermatology and Venereology; Martin Luther University Halle-Wittenberg; D-06120 Halle (Saale) Germany
3. Information Network of Departments of Dermatology (IVDK); Georg August University Göttingen; D-37075 Göttingen Germany