1. Department of Dermatology, Competence Center for Chronic Pruritus University Hospital of Münster Münster Germany
2. Institute of Medical Informatics University of Münster Münster Germany
3. Department of Dermatology University of Copenhagen Copenhagen Denmark
4. Institute for Health Services Research in Dermatology and Nursing University Medical Center Hamburg‐Eppendorf Hamburg Germany
5. Department of Dermatology Oslo University Hospital Oslo Norway
6. Department of Health, Medical and Neuropsychology Institute of Psychology Leiden University Leiden The Netherlands
7. Catholic University of the Sacred Heart, Milano Lombardy Italy
8. Department of Dermatology University Hospital and Faculty of Medicine University of Coimbra Coimbra Portugal
9. Department of Dermatology University Hospital of Antwerp Antwerp Belgium
10. Department of Dermatology Medical University of Graz Graz Austria
11. Royal Free London and St John's Institute of Dermatology Guy's & St Thomas’ Hospital London United Kingdom
12. Department of Dermatology University Hospital of Brest Brest France
13. Department of Dermatology and Allergy Hannover Medical School Hannover Germany
14. Department of Dermatology, Venereology and Allergology Wroclaw Medical University Wroclaw Poland
15. Department of Dermatology Adnan Menderes University Aydın Turkey
16. Department of Dermatology Kantonsspital Aarau Aarau Switzerland
17. Cutaneous Allergy Unit Department of Dermatology Hospital Sant Pau Universitat Autònoma Barcelona Barcelona Spain
18. Department of Dermatology and Venereology University Hospital of Lund Lund Sweden
19. Department of Social Medicine, Occupational and Environmental Dermatology University of Heidelberg Heidelberg Germany