1. Department of Dermatology, Inselspital; Bern University Hospital; Bern Switzerland
2. Centro Studi GISED; Bergamo Italy
3. Department of Dermatology; University Hospital Zurich; Zurich Switzerland
4. Department of Dermatology; University Hospital of Lausanne CHUV; Lausanne Switzerland
5. Department of Dermatology; University Hospital Basel; Basel Switzerland
6. Department of Dermatology; Cantonal Hospital St. Gallen; St. Gallen Switzerland
7. Department of Dermatology; Cantonal Hospital Aarau; Aarau Switzerland
8. Department of Dermatology; Geneva University Hospitals (HUG); Geneva Switzerland
9. Department of Clinical Social Medicine, Occupational and Environmental Dermatology; University Hospital; Ruprecht Karls University; Heidelberg Germany
10. Institute of Epidemiology and Preventive Medicine; University of Regensburg; Regensburg Germany