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