A woman in her 80s presented with a 1-week history of progressive, painful blisters and ulcers of the groin. This was associated with enlargement of the tongue over the past 3 months, leading to difficulty with mastication. She also reported numbness with no associated weakness of her distal lower limbs for 3 months. This restricted her mobility to the extent that she required diapers. However, she declined any further investigations for her peripheral neuropathy. She had IgG λ-type multiple myeloma complicated by anemia and lytic lesions in the calvarium, which was managed conservatively with transfusions. She was taking folic acid and intramuscular cyanocobalamin supplements owing to deficiencies attributed to a dietary cause. On examination, there were circinate purpuric patches with erosions on the natal cleft, buttocks, inguinal creases, and vulva (Figure, A). Hemorrhagic flaccid bullae were observed on the posterior perineum. This was accompanied by macroglossia, glossitis, and a hemorrhagic erosion on the hard palate (Figure, B). There were purpuric macules periorbitally and on the lips, inframammary folds, forearms, and thighs. Laboratory findings revealed a platelet count of 171 × 103/μL (reference range, 140-440 × 103/μL), prothrombin time of 11.7 seconds (reference range, 9.9-11.4 seconds), activated partial thromboplastin time of 36.0 seconds (reference range, 25.7- 32.9 seconds), and serum zinc levels of 34.4 μg/dL (reference range, 72.4-124.4 μg/dL). (To convert zinc to micromoles per liter, multiply by 0.153.) Results from initial punch biopsies from a purpuric macule on the right inframammary fold and a blister at the perineum were inconclusive. A repeated biopsy from a hemorrhagic blister at the left groin was performed (Figure, C and D).
Tay YE, Busmanis I, Lee HY. Blistering Eruption of the Buttocks. JAMA Dermatol. 2015;151(12):1367-1368. doi:10.1001/jamadermatol.2015.2876