1. Institute for Prevention and Occupational Medicine of the German Social Accident Insurance, Institute of the Ruhr-University Bochum (IPA); Ruhr-University Bochum; 44789 Bochum Germany
2. DRK-Blood Transfusion Service West; Centre for Transfusion Medicine Breitscheid; 40885 Ratingen Germany
3. Klinik für Dermatologie; Allergologie und Venerologie Medizinische Hochschule; 30625 Hannover Germany
4. Department of Dermatology, Venereology and Allergology, St. Josef-Hospital; Ruhr-University Bochum; 44791 Bochum Germany
5. Department of Clinical Social Medicine, Centre of Occupational and Environmental Dermatology; Heidelberg University Hospital; 69115 Heidelberg Germany
6. Department of Dermatology; Universitätsklinikum Carl Gustav Carus; 01307 Dresden Germany
7. Department of Dermatology; Jena University Hospital; 07743 Jena Germany
8. Dermatologikum Hamburg; 20354 Hamburg Germany
9. Berufsgenossenschaftliches, Unfallkrankenhaus Hamburg Dermatologie; 21033 Hamburg Germany
10. Department of Dermatology and Allergy, Allergy-Center Charite; Universitätsmedizin Berlin; 10117 Berlin Germany
11. Department of Dermatology and Allergy; Ludwig Maximilian University; 80337 Munich Germany
12. Department of Dermatology, Environmental Medicine and Health Theory; University of Osnabrück; 49090 Osnabrück Germany
13. Department of Dermatology; University Hospital Heidelberg; 69120 Heidelberg Germany
14. Department of Occupational Dermatology; Berufsgenossenschaftliche-Klinik Falkenstein; 08223 Falkenstein Germany
15. Department of Dermatology; Saarland University Medical School; 66424 Homburg Saar Germany
16. Department of Dermatology; Bethesda Hospital; 57258 Freudenberg Germany
17. Department of Dermatology and Venereology; Martin Luther University Halle-Wittenberg; 06120 Halle Saale Germany
18. Department of Dermatology; SLK Hospital Heilbronn; 74078 Heilbronn Germany
19. Information Network of Departments of Dermatology (IVDK); Georg-August-University Göttingen; 37075 Göttingen Germany