[1] Univ Zurich Hosp, Dept Dermatol, CH-8091 Zurich, Switzerland
[2] Univ Zurich, Inst Social & Prevent Med, CH-8006 Zurich, Switzerland
[3] Klinikum Ernst Von Bergmann, Dept Dermatol, Potsdam, Germany
[4] Univ Jena, Dept Dermatol, D-6900 Jena, Germany