Brunsting-Perry type localized bullous pemphigoid, possibly induced by furosemide administration and sun exposure

A 56-year-old male visited our hospital complaining of irregular-shaped atrophic erythematous plaques with blood crust, erosion, pigmentation, and depigmentation, localized on his forehead, bilateral cheeks, and ear lobes, for over one year. He has been receiving peritoneal dialysis and furosemide administration due to chronic renal failure for four years. Direct immunofluorescence examination exhibited linear depositions of IgG and C3 in the basement membrane zone. Antibodies against the recombinant NC16a-domain of BP180 were negative by enzyme-linked immunosorbent assays (ELISA), though BP230 ELISA was positive. Immunoblotting using extracts of normal human epidermis demonstrated that the patient's serum reacted with BP180 and BP230. IgG class autoantibodies to recombinant proteins of the C-terminal domain of BP180 were also detected by immunoblotting. This case was diagnosed as localized bullous pemphigoid (LBP). Oral administration of prednisolone 10 mg daily was started and furosemide administration was ceased. The eruptions disappeared thereafter with superficial scars. This is the second reported case of Brunsting-Perry type LBP associated with IgG class autoantibodies to the C-terminal domain of BP180. Furthermore, photosensitivity caused by furosemide administration may contribute to the induction and exacerbation of the lesions.