1. Institute for Health Services Research in Dermatology and Nursing (IVDP) University Medical Center Hamburg‐Eppendorf (UKE) Hamburg Germany
2. Psoriasis Center Department of Dermatology University Medical Center Schleswig‐Holstein Kiel Germany
3. Dermatology Office and Dermatology Study Center (CMSS) Dr. Ralph von Kiedrowski Selters/Westerwald Germany