Varicella zoster virus presenting as lower extremity ulcers
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A 75-year-old man with a thirty-five-year history of Crohn’s disease on methotrexate presented with a few months of progressive left lower extremity ulcerations and new ipsilateral palpable purpura. Past medical history was significant for left foot osteomyelitis resulting in toe amputations and a macrocytic anemia of unknown etiology with normal vitamin B12 and folate levels. A recent empiric systemic prednisolone taper (80mg to 40mg PO daily) elicited no improvement over the past few weeks, and the patient reported evolution of left lower extremity palpable purpura.

Physical examination revealed large ovoid ulcers with eschars of the posterolateral left leg and dorsal foot and palpable purpura extending proximally to the knee. Concurrent cribriform ulcerations coalesced over the left ankle and dorsal foot. A skin biopsy near the edge of an ovoid ulcer of the left leg revealed a perivascular and interstitial mixed infiltrate predominantly composed of cells with pleomorphic nuclei, prominent nucleoli, and ample granular cytoplasm with overlying focal vacuolar change and mild papillary dermal edema.

Subsequent skin biopsy of a purpuric papule demonstrated ballooning degeneration of keratinocytes forming an intraepidermal vesicle with adjacent basal vacuolar change; immunohistochemistry and PCR confirmed varicella zoster virus (VZV) and ruled out herpes simplex virus and cytomegalovirus. Oral valacyclovir (one gram three times daily) effected marked cutaneous improvement after four weeks. Therapy was continued for a full six weeks duration.

This case emphasizes the necessity of careful clinicopathological correlation to navigate the varied presentations of VZV and broadens reported histopathologic findings to include an atypical myeloid infiltrate mimicking leukemia cutis in a dual immunosuppressed patient.