1. German Center for Health Services Research in Dermatology (CVderm); Institute for Health Services Research in Dermatology and Nursing (IVDP); University Medical Center Hamburg-Eppendorf (UKE); Hamburg Germany
2. Department of Dermatology; Elbe Kliniken Buxtehude; Buxtehude Germany
3. Department of Dermatology; University of Kiel; Kiel Germany