Pemphigus Vulgaris Presenting as Severe Crusted Lesions of the Lower Lip: A Case Report

Pemphigus vulgaris (PV) is a rare autoimmune blistering disease of the skin and mucous membranes. The oral cavity is frequently the first, and sometimes the only, site involved, and crusted or erosive lesions may be mistaken for malignancy. A 70-year-old woman in good general health was referred for crusted lesions on an erythematous background involving the entire lower lip and its inner surface, highly suspicious of malignancy. An erosive plaque of the right buccal mucosa, measuring 2 cm along its longest axis, with raised borders and surrounding erythema, had been evolving for 3 months. No other cutaneous site was involved, and the Nikolsky sign was positive. Biopsies of two lesions were performed. Histopathology and direct immunofluorescence (DIF) were consistent with pemphigus vulgaris. The patient received local prednisone 20 mg daily together with topical treatment of the labial lesions. Marked clinical improvement was observed after 2 months of treatment. Lessons. Severe crusted lip lesions in an older adult can present as PV rather than carcinoma. Early biopsy with DIF, and attention to a positive Nikolsky sign, allow prompt diagnosis and treatment of an otherwise misleading presentation.