A 26-year-old, previously healthy man presented to the emergency department with fever and rash of 5 days’ duration. He had initially noted small, erythematous “red spots” on the soles of his feet, which evolved into diffusely tender and coalescent blisters, with progressive involvement of both thighs. Self-treatment with antifungal cream had provided no relief. Physical examination revealed numerous violaceous, palpable, nonblanching, and indurated purpuric lesions of differing sizes on the arms and legs (Figure). All the lesions were tender to palpation. Urinalysis showed microscopic hematuria. Immunologic workup was negative, except for an antinuclear antibody titer of 1:40. A biopsy revealed the diagnosis.

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