1. Department of Dermatology, Venerology and Allergology, University of Essen, Essen, Germany
2. University Medical Center Hamburg-Eppendorf, Hamburg, Germany
3. Specialist Practice for Diabetology, Stadtbergen, Germany
4. MEDAHCON GmbH, HealthCare Communication, Bonn, Germany
5. Specialist Practice for Diabetology and Nutritional Medicine, Münster, Germany
6. Department of Endocrinology, Diabetology and Geriatrics, Stuttgart General Hospital, Bad Cannstatt, Stuttgart, Germany
7. Joint Dermatology Practice Bramfeld, Hamburg, Germany
8. Department of Dermatology and Venerology, State Hospital and Academic Teaching Hospital Feldkirch, Feldkirch, Austria
9. Department of Dermatology, Ruhr-University Bochum, Bochum, Germany
10. Department of Surgery, Venenklinik Bellevue, Kreuzlingen, Switzerland
11. Dermatology Group Practice, Freiburg, Germany
12. University Hospital Zurich, Department of Dermatology, Zurich, Switzerland