Multiple-Site Lichen Planus: An Italian Case Series of 44 Patients

<b>Background</b>: Lichen planus (LP) is a chronic immune-mediated inflammatory disorder affecting skin, mucosae, nails, and appendages, often with significant impact on quality of life. While associations between oral LP (OLP) and other localizations have been described, comprehensive analyses of patients presenting with multiple LP localizations remain limited. The aim of the study was describing the association of multisite LP among our patients in order to contribute to knowledge about this rare, but possible, clinical situation and its clinical implications in terms of follow-up. <b>Methods</b>: We conducted a retrospective observational study including 44 adult patients with histologically confirmed OLP and at least two additional LP subtypes. Data were collected at the joint dermatology-oral pathology clinic of Policlinico Sant'Orsola Malpighi, Bologna, between January 2022 and December 2024. Demographic characteristics, clinical manifestations, comorbidities, and therapeutic approaches were analyzed. <b>Results</b>: The cohort comprised 31 women and 13 men (mean age at first LP diagnosis: 56 years). All patients presented OLP, predominantly erosive (73%). During a follow-up, 39 patients developed three LP subtypes, and 5 patients developed four LP subtypes. Cutaneous LP was universal, while mucosal involvement included genital LP (<i>n</i> = 23), esophageal/pharyngeal/laryngeal LP (<i>n</i> = 8), and vulvar lichen sclerosus (<i>n</i> = 6). Nail LP was diagnosed in seven cases and frontal fibrosing alopecia in ten cases. Autoimmune comorbidities were frequent, including thyroiditis, psoriasis, systemic sclerosis, lupus, and Sjögren's syndrome. First-line therapy consisted of topical and systemic corticosteroids, with adjuvant retinoids, cyclosporine, or immunosuppressants in refractory cases. No malignant transformation or dysplasia was detected during the observation period, and the mean follow-up period was 24 months (range: 12-36 months). <b>Conclusions</b>: Multisite LP is a complex, underrecognized condition requiring multidisciplinary management. OLP frequently represents the initial manifestation, followed by progressive involvement of cutaneous and mucosal sites. Regular full-body, oral, and genital examinations, together with tailored systemic treatments, are essential to prevent scarring sequelae and improve quality of life. Our findings highlight the need for heightened clinical vigilance and integrated care pathways for patients with multi-site LP.