1. Department of Dermatology; Venereology and Allergology; University Medical Center Essen; Essen Germany
2. Department of Dermatology; Venereology and Allergology; University Medical Center Erlangen; Erlangen Germany
3. Department of Dermatology; Division of Wound Healing/Phlebology; University Medical Center Münster; Münster Germany
4. Department of Vascular Medicine; HELIOS Klinikum Krefeld; Krefeld Germany
5. Department of Dermatology; Venereology and Allergology; University Medical Center Bochum; Bochum Germany