1. Department of Medical Informatics, Biometry and Epidemiology; Friedrich-Alexander University Erlangen-Nürnberg; 91054 Erlangen Germany
2. Department of Dermatology; Hospital del Mar, Institut Mar d'Investigacions Mediques, Universitat Autónoma; 08003 Barcelona Spain
3. Department of Dermatology; University of Witten/Herdecke and Klinikum Dortmund (formerly); 44137 Dortmund Germany
4. Department of Dermato-Allergology; National Allergy Research Centre, Gentofte Hospital, University of Copenhagen; 2900 Hellerup Denmark
5. Dermatology; University Medical Centre Groningen, University of Groningen; 9700 RB Groningen The Netherlands
6. Department of Dermatology; VU University Medical Centre; 1081 HV Amsterdam The Netherlands
7. Department of Public Health; Occupational Medicine, University of Trieste; IT-34129 Trieste Italy
8. Department of Dermatology; University Medical Centre Maribor; 2000 Maribor Slovenia
9. Allergy Unit, Department of Dermatology; University Hospital; 4031 Basel Switzerland
10. Spire Hospital; Leeds LS8 1NT UK