1. Institute for Health Services Research in Dermatology and Nursing (IVDP), University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
2. Psoriasis-Center Kiel, Department of Dermatology, Venerology and Allergology, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
3. Dermatological Practice, Selters, Germany
4. Almirall Hermal GmbH, Reinbek, Germany