1. Department of Medical Sciences, Dermatology Clinic University of Turin Turin Italy
2. Dermatology Unit Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milan Italy
3. Department of Pathophysiology and Transplantation Università degli Studi di Milano Milan Italy
4. Dermatology Unit IRCCS of Azienda Ospedaliero‐Universitaria di Bologna Bologna Italy
5. Dermatology, Department of Experimental, Diagnostic and Specialty Medicine (DIMES) University of Bologna Bologna Italy
6. Hematopathology Unit, Department of Experimental, Diagnostic and Specialty Medicine University of Bologna Bologna Italy
7. Hematology‐BMT Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, University of Milan Milan Italy
8. Inter‐Hospital Pathology Division IRCCS MultiMedica Milan Italy