1. Department of Dermatology; Competence Center for Chronic Pruritus; University Hospital Münster; Münster Germany
2. Competence Center for Healthcare Research in Dermatology (CVderm); Institute for Healthcare Research in Dermatology and Nursing (IVDP); University Hospital of Hamburg-Eppendorf; Hamburg Germany
3. Moscow Scientific and Practical Center of Dermatovenerology and Cosmetology; Moscow Russia
4. Department of Dermatology and Venereology; Skåne University Hospital; Lund University; Malmö Sweden
5. Department of Dermatology; University Hospital Gentofte; Copenhagen Denmark
6. Institute of Dermatology; Catholic University of the Sacred Heart; Rome Italy
7. Justus Liebig University; Giessen Germany
8. Department of Dermatology; University Hospital and Faculty of Medicine; University of Coimbra; Coimbra Portugal
9. Department of Dermatology; Oslo University Hospital; University of Oslo; Oslo Norway
10. Department of Dermatology; Royal Free Hospital; London UK
11. Department of Dermatology and Allergy; Charité - Universitätsmedizin Berlin; Berlin Germany
12. Department of Dermatology; University of Rzeszow; Rzeszow Poland
13. Department of Dermatology; Adnan Menderes University; Aydın Turkey
14. Department of Psychosomatics and Psychotherapy; Münster University Hospital; Münster Germany
15. Department of Dermatology; Cutaneous Allergy Unit; Hospital Sant Pau; Universitat Autònoma Barcelona; Barcelona Spain
16. Dermatological Practice; Bad Bentheim and Department of Dermatology; Klinikum Dortmund GmbH; Dortmund Germany
17. Department of Dermatology; Kantonsspital Aarau; Aarau Switzerland
18. Department of Dermatology and Venereology; Skåne University Hospital SUS Lund; Lund University; Lund Sweden
19. Department of Dermatology and Allergology; Ludwig Maximilian University; Munich Germany
20. Institute of Medical Informatics; University of Münster; Münster Germany
21. Department of Social Medicine, Occupational and Environmental Dermatology; University of Heidelberg; Heidelberg Germany
22. Department of Dermatology, Venereology and Allergology; Wroclaw Medical University; Wroclaw Poland
23. Department of Dermatology; Medical University of Graz; Graz Austria