[1] Univ Hosp Bern, Inselspital, Dept Dermatol, CH-3010 Bern, Switzerland
[2] Ctr Studi GISED, Bergamo, Italy
[3] Univ Zurich Hosp, Dept Dermatol, CH-8091 Zurich, Switzerland
[4] Univ Hosp Lausanne CHUV, Dept Dermatol, Lausanne, Switzerland
[5] Univ Basel Hosp, Dept Dermatol, CH-4031 Basel, Switzerland
[6] Cantonal Hosp St Gallen, Dept Dermatol, St Gallen, Switzerland
[7] Cantonal Hosp Aarau, Dept Dermatol, Aarau, Switzerland
[8] Geneva Univ Hosp HUG, Dept Dermatol, Geneva, Switzerland
[9] Heidelberg Univ, Univ Hosp, Dept Clin Social Med Occupat & Environm Dermatol, Heidelberg, Germany
[10] Univ Regensburg, Inst Epidemiol & Prevent Med, D-93053 Regensburg, Germany