J M P A van den Reek1, W Kievit2, E M G J de Jong3. 1. Department of Dermatology, Radboud University Medical Center, Nijmegen, The Netherlands. Electronic address: Juul.vandenReek@Radboudumc.nl. 2. Department of Health Evidence, Radboud Institute of Health Sciences, Nijmegen, The Netherlands. 3. Department of Dermatology, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud University, Nijmegen, The Netherlands.