1. Institute for Health Services Research in Dermatology and Nursing (IVDP); German Center for Health Services Research in Dermatology (CVderm); University Clinics of Hamburg-Eppendorf; Hamburg Germany
2. Department of Dermatology, Venereology and Allergology; University of Essen; Essen Germany
3. Department of Dermatology; Helios Clinics Duisburg; Duisburg Germany