1. Department of Dermatology; University Hospital Jena, Erfurter Strasse 35; D-07743; Jena; Germany
2. Department of Dermatology, Environmental Medicine; University of Osnabrueck; D-49069 Osnabrück; Germany
3. Department of Social Medicine, Occupational and Environmental Dermatology; University of Heidelberg; D-69115 Heidelberg; Germany