Unusual Presentation of Pemphigus Vulgaris as a Solitary Ulcerative Scalp Lesion: A Case Report.

Pemphigus vulgaris (PV) is a rare autoimmune blistering disease that typically presents with painful oral erosions followed by widespread cutaneous involvement. We report a diagnostically challenging case of PV in a 43-year-old man who initially presented with a solitary, ulcerative-crusted lesion on the parietal scalp, evolving over eight months. The lesion was clinically suggestive of infectious or neoplastic etiologies, including tinea capitis, squamous cell carcinoma, Bowen's disease, and leishmaniasis. Empirical antifungal treatment was ineffective, and mycological studies were negative. Dermoscopy revealed yellow crusts, serpentine vessels, and perifollicular whitish halos. The patient later developed painful oral ulcers, which led to histopathological and immunofluorescence studies confirming PV. Systemic corticosteroids and mycophenolate mofetil were initiated with marked clinical improvement. This case highlights an uncommon presentation of PV that delayed diagnosis and emphasizes the importance of considering autoimmune bullous disorders in the differential diagnosis of chronic, non-healing scalp lesions, even in the absence of mucosal involvement.