Bullous herpes zoster masquerading as a bullous pemphigoid flare: A case report.

Herpes zoster (HZ) results from the reactivation of dormant varicella zoster virus (VZV) in the posterior dorsal root ganglia manifesting as painful vesicles along the dermatomal distribution as shingles. The risk of reactivation is higher in immunocompromised patients. Herpes zoster lesions can have varied presentations including bullous forms, may induce BP flare, may co-exist in the same lesions, and should be included in the list of differentials for BP flares not responding to the standard of care. Here, we describe a case of a 74-year-old female with a history of recurrent bullous pemphigoid (BP) flares, who was on mycophenolate mofetil, and presented with skin lesions on her right thigh which were typical for her BP flares. Unlike prior flares, the lesions did not respond to prednisone therapy. Her hospitalization course was complicated by encephalopathy. Intravenous acyclovir was started empirically. Viral cultures and polymerase chain reaction from the lesions came back positive for VZV, but the patient succumbed to her illness shortly afterward.