Oral terbinafine-induced bullous pemphigoid

OBJECTIVE: To report a case of drug-induced bullous pemphigoid (BP) in an otherwise healthy elderly patient after taking terbinafine for 20 days. CASE SUMMARY: A 78-year-old man presented with distal subungual onychomycosis of the toenails. Oral terbinafine 250 mg/d was started for treatment. Twenty days after the beginning of the treatment, the patient presented with widespread pruritic blistering eruption, more severe on the extremities. He had not received terbinafine before and was not receiving any other drug. The diagnosis of BP was confirmed with histopathologic examination. The patient was treated successfully with oral steroids. DISCUSSION: Drug-induced BP is a well-known complication of many drugs and represents a spectrum from an acute and self-limited condition to a chronic disease. Terbinafine is frequently used in the elderly. It is known to have less drug interactions and adverse effects compared with the other antifungal agents. Use of the Naranjo probability scale indicated a probable relationship between BP and terbinafine treatment in this patient. CONCLUSIONS: To the best of our knowledge, this is the first report in the English-language literature of BP in a patient taking terbinafine. As with any other medication, oral terbinafine has the potential for severe adverse reactions. Healthcare professionals should be aware of this possibility.