1. Department of Dermatology, Venereology and Allergology; University Hospital of Essen; Essen Germany
2. Department of Dermatology and Venereology; University Hospital of Magdeburg; Magdeburg Germany
3. Institute for Healthcare Research of Dermatology and Health Care Professions; University Hospital of Hamburg; Hamburg Germany
4. Department of Dermatology, Allergology and Environment Medicine; Clinical Centre Schwabing Munich; Munich Germany
5. Department of Dermatology and Venereology; University Hospital of Erlangen; Erlangen Germany
6. Department of Dermatology, Centre for venous disease of the dermatological and vascular surgery; University Hospital of Bochum; Bochum Germany
7. Department of Dermatology and Venereology; University Hospital of Frankfurt a. M.; Frankfurt Germany
8. Department of Dermatology, Venereology and Allergology; Hospital Dresden-Friedrichstadt; Dresden Germany
9. Department of Dermatology, Venereology; University Hospital of Kiel; Keil Germany
10. Department of Dermatology, Venereology; University Hospital of Regensburg; Regensburg Germany
11. General Medical Department; Timaru Public Hospital, SCDHB; Timaru New Zealand