1. Information Network of Departments of Dermatology (IVDK) Institute at the University Medical Center Göttingen Göttingen Germany
2. Department of Dermatology, ‘Tattoo’ Consultation Bichat‐Claude Bernard Hospital, Assistance Publique ‐ Hôpitaux de Paris Paris France
3. Department of Dermatology University of Helsinki and Helsinki University Central Hospital Helsinki Finland
4. Department of Chemical and Product Safety German Federal Institute for Risk Assessment (BfR) Berlin Germany