1. Department of Dermatology; Faculty of Medicine; Eberhard Karls University Tuebingen; Tuebingen Germany
2. Department of Clinical Epidemiology and Applied Biostatistics; Faculty of Medicine; Eberhard Karls University Tuebingen; Tuebingen Germany
3. Baden-Württemberg State Health Office; District Government Stuttgart; Stuttgart Germany
4. Department of Dermatology and Allergy Biederstein; Technische Universität; Munich Germany