1. Department of Dermatology University Hospital Zurich Gloriastraße 31 Zürich Switzerland
2. Department of Dermatology University of Tübingen Liebermeisterstrasse 25 72076 Tübingen Germany
3. Washington Hospital Center Department of Dermatology Georgetown University Washington DC U.S.A
4. Medical Directorate University Hospital of Zürich Rämistraße 100 8091 Zürich Switzerland
5. Department of Dermatology University Hospital Regensburg Franz‐Josef‐Strauss‐Allee 11 D‐93053 Regensburg Germany