1. Department of Dermatology; University Hospital-Inselspital Bern; University of Bern; Bern Switzerland
2. Section of Dermatology; Department of Medical Sciences; University of Turin; Turin Italy
3. Department of Oral Surgery and Stomatology; School of Dental Medicine; University of Bern; Bern Switzerland
4. Department of Dermatology; Azienda Ospedaliera Papa Giovanni XXIII; Bergamo Italy