1. Department of Dermatology and Allergy University Hospital of Bonn Bonn Germany
2. Department of Dermatology University Hospital Zurich Zurich Switzerland
3. Faculty of Medicine University Zurich Zurich Switzerland
4. Department of Dermatology and Venereology Móstoles Hospital Madrid Spain
5. Hochgebirgsklinik Davos Davos Switzerland
6. Department of Dermatology and Venereology Plató Hospital Barcelona Spain