1. Department of Dermatology, Hôpital Erasme Université Libre de Bruxelles Brussels Belgium
2. Department of Dermatology, Institute Jules Bordet Université Libre de Bruxelles Brussels Belgium
3. Department of Cutaneous Allergy St John's Institute of Dermatology, Guy's Hospital London UK
4. Department of Dermatology and Venereology CHUV, University of Lausanne Lausanne Switzerland
5. Molecular and Pharmaco‐Epidemiology Unit, Department of Experimental Oncology European Institute of Oncology, IRCCS Milan Italy