1. Department of Dermatology and Allergy; Ludwig Maximilian University; Frauenlobstr. 9-11 80337 Munich Germany
2. Department of Dermatology; University Hospital Carl Gustav Carus, Technical University Dresden; Fetscherstraße 74 01307 Dresden Germany
3. Information Network of Departments of Dermatology; Georg-August University; von-Sieboldstr. 3 37075 Göttingen Germany