1. Department of Dermatology; The Leeds Teaching Hospitals NHS Trust; Leeds LS7 4SA UK
2. Department of Dermatology; University Allergy Centre, University Hospital Carl Gustav Carus, Technical University Dresden; Dresden D-01307 Germany
3. Welsh Institute of Dermatology; Cardiff CF14 4XN UK
4. Department of Dermatology; Churchill Hospital; Oxford OX3 7LJ UK
5. Nofer Institute of Occupational Medicine; Lodz 91-348 Poland
6. Department of Public Health, Occupational Medicine; University of Trieste; IT-34129 Trieste Italy
7. Allergy Unit, Department of Dermatology; University Hospital Erlangen; 91054 Erlangen Germany
8. Department of Dermatology; Hospital Universitario de la Princesa; 28006 Madrid Spain
9. Information Network of Departments of Dermatology; University Medicine Göttingen; 37075 Göttingen Germany
10. Department of Medical Informatics, Biometry and Epidemiology; University of Erlangen/Nurnberg; 91054 Erlangen Germany