1. Department of Dermatology; VU Medical Center; Amsterdam; The Netherlands
2. Centrum Oosterwal; Alkmaar; The Netherlands
3. Red Cross Hospital; Beverwijk; The Netherlands
4. Groene Hart Hospital; Gouda; The Netherlands
5. Waterland Hospital; Purmerend; The Netherlands
6. Department of Epidemiology and Biostatistics; VU Medical Center; Amsterdam; The Netherlands
7. Department of Pathology; VU Medical Center; Amsterdam; The Netherlands