1. Department of Dermatology; Papageorgiou Hospital; Aristotle University of Thessaloniki; Thessaloniki Greece
2. Department of Dermatology; St. Pierre Hospital; Brussels Belgium
3. Artistotle University of Thessaloniki; Thessaloniki Greece
4. Department of Dermatology; Sir Paul Boffa Hospital; Floriana Malta
5. Department of Dermatology and Venereology; Medical University of Warsaw, Warsaw; Poland
6. Department of Clinical Epidemiology and Biostatistics; Faculty of Medicine, Pontificia Universidad Javeriana; Bogotá Colombia