AbstractBehçet’s disease (BD) is a heterogeneous multifactorial autoinflammatory disease characterized by a plethora of clinical manifestations. Cutaneous lesions are considered hallmarks of the disease. However, their evolution over time and a thorough description are scarcely reported in non-endemic regions. The aim of this study was to detail BD skin manifestations and their evolution over time in Italy, as well as the dermatological prognostic impact of specific cutaneous features in long-standing disease. Data were collected in a double fashion, both retrospectively and prospectively, from the AutoInflammatory Disease Alliance (AIDA) international registry dedicated to BD, between January 2022 and December 2022. A total of 458 Italian patients were included. When assessing skin manifestations course, the constant or sporadic presence or absence of cutaneous involvement between onset and follow-up was considered. Oral ulcers (OU) (88.4%) and genital ulcers (GU) (52.6%), followed by skin involvement (53.7%) represented the most common presenting mucocutaneous manifestations at disease onset. Up to the time of enrolment into the AIDA registry, 411 (93.8%) patients had suffered from OU and 252 (57.9%) from GU; pseudofolliculitis (PF) accounted for the most common skin manifestation (170 patients, 37.1%), followed by erythema nodosum (EN) (102 patients, 22.3%), skin ulcers (9 patients, 2%) and pyoderma gangrenosum (4 patients, 0.9%). A prospective follow-up visit was reported in 261/458 patients; 24/148 (16.2%) subjects with skin involvement as early as BD onset maintained cutaneous lesions for the entire period of observation, while 120 (44.1%) patients suffered from sporadic skin involvement. Conversely, 94/113 (83.2%) with no skin involvement at disease onset did not develop skin lesions thereafter. At follow-up visits, cutaneous involvement was observed in 52 (20%) patients, with a statistically significant association between PF and constant skin involvement (p = 0.031). BD in Italy is characterized by a wide spectrum of clinical presentations and skin manifestations in line with what is described in endemic countries. Patients with skin disease at the onset are likely to present persistent cutaneous involvement thereafter; mucocutaneous lesions observed at the onset, especially PF, could represent a warning sign for future persistent skin involvement requiring closer dermatological care.