Abstract: Bullous pemphigoid is the most frequent autoimmune bullous disease and mainly affects elderly individuals. The target antigens are mainly BP180 and BP230 located in the basement membrane, the lesions are common on the trunk and the flexion side of the limbs. About 10%-30% of patients have mucosal lesions, and the oral mucosa is the most commonly involved. Herein, we report a case of bullous pemphigoid with genital erosive ulcer as the first symptom. A 60-year-old male patient presented with a 4-month history of recurrent erosions and ulceras on his penile, and repeated rice-sized blisters of on the chest for 1 month, and. Nikolsky's sign was negative. The histopathological examination revealed old blister under the epidermis and lymphocytes, eosinophils infiltration in the superficial dermis. Direct immunofluorescence showed linear deposition of C3 along the basal membrane band. The anti-BP180 antibodies, anti-BP230 antibodies and anti-type VII collagen antibodies were negative. The diagnosis of bullous pemphigoid was made. The patient was treated with prednisone acetate, centella and nicotinamidethe, genital erosions and chest blister healed half a month later，glans ulcers healed completely after 2.5 months, the drug was stopped half a year later, and there was no recurrence during 2 years follow-up.

Key words: bullous pemphigoid, genital, mucosal lesion