1. Department of Dermatology; Leiden University Medical Center; the Netherlands
2. Department of Dermatology; Academic Medical Center and Vrije University Medical Center; Amsterdam the Netherlands
3. Department of Dermatology; Erasmus Medical Center; Rotterdam the Netherlands
4. Department of Dermatology; University Medical Center of Groningen; the Netherlands
5. Department of Dermatology; Radboud University Medical Center; Nijmegen the Netherlands
6. Department of Dermatology; University Medical Center Utrecht; the Netherlands
7. Department of Dermatology; Maastricht University Medical Center; the Netherlands