A case of chronic herpes gestationis: persistent disease or conversion to bullous pemphigoid?

We report the case of a 38-year-old woman with herpes gestationis (HG) persistent for 26 months postpartum with typical erythematous-edematous grouped lesions associated with vesicles, blisters, and scaled crusts on most parts of her body. Despite high doses of oral prednisolone, azathioprine, and dapsone, and a trial of 5 plasmaphereses, the disease has persisted to date. Histopathologic examination of lesional skin showed subepidermal blisters, focal basal cell necrosis, and a dermal inflammatory infiltrate including many eosinophils. Direct immunofluorescence showed linear C3 staining in the basement membrane zone and the complement fixation test demonstrated circulating antibasement membrane zone antibodies at a low titer (1:80). HLA typing demonstrated an A2, A24, B35, B52, DR4,5, DR13,15, DRW52,53 phenotype. We present this case as chronic persistent HG and discuss the differential diagnosis between chronic persistent HG and HG evolving to bullous pemphigoid, together with a careful examination of similar cases reported in literature.