1. Department of Dermatology; University of Witten/Herdecke; 58448 Witten Germany
2. Department of Dermatology; Klinikum Dortmund; 44137 Dortmund Germany
3. Department of Dermato-Allergology; National Allergy Research Centre, Gentofte Hospital, University of Copenhagen; 2900 Hellerup Denmark
4. Dermatology; University Medical Centre Groningen, University of Groningen; 9700 RB Groningen The Netherlands
5. Department of Dermatology; Hospital General Universitario de Alicante; 03010 Alicante Spain
6. Department of Dermatology; Hospital Universitario la Princesa; 28006 Madrid Spain
7. Department of Clinical Social Medicine; University Hospital Heidelberg; 69115 Heidelberg Germany
8. Department of Medical Informatics, Biometry and Epidemiology; Friedrich-Alexander University Erlangen-Nürnberg; 91054 Erlangen Germany