1. Department of Dermatology and Allergy, National Allergy Research Centre; Copenhagen University Hospital Herlev and Gentofte; 2900 Hellerup Denmark
2. Department of Environmental Science; Aarhus University; 4000 Roskilde Denmark
3. St John's Institute of Dermatology; Guy's Hospital; London SE1 9RT UK
4. Laboratoire de Dermatochimie; CNRS and University of Strasbourg; 67091 Strasbourg France
5. Institute of Environmental Medicine; Karolinska Institutet; 171 77 Stockholm Sweden
6. Department of Medical Informatics, Biometry and Epidemiology; Friedrich-Alexander University; 91054 Erlangen Germany