Epidemiology and pathogenesis / Vincenzo Bettoli and Giulia Ruina -- Clinical features and diagnostic clues / Maria Letizia Musumeci, Maria Rita Nasca, Piera Catalfo, Karishma Bhatt, and Giuseppe Micali -- Histopathology / Franco Rongioletti -- Classification and severity scales / Giuseppe Monfrecola and Matteo Megna -- Correlation between severity and its impact on quality of life / Nevena Skroza and Maria Concetta Potenza -- Comorbidities and complex syndromes / Gabriella Fabbrocini and Valerio De Vita -- Complications / Teresa Oranges, Valentina Dini, Andrea Chiricozzi, Salvatore Panduri, and Marco Romanelli -- Ultrasound imaging / Antonio Martorell -- Radiological imaging / Giuseppe Petrillo, Stefano Palmucci, and Claudia Trombatore -- Skin imaging : dematoscopy and videodermatoscopy / Francesco Lacarrubba, Anna Elisa Verzì, Federica Fiorentini, and Giuseppe Micali -- Differential diagnosis / Stefano Veraldi, Elena Guanziroli, and Mauro Barbareschi.