Purpuric Eruption With Bloody Diarrhea in an Adult

REPORT OF A CASE An 18-year-old white man was admitted to the Internal Medicine Service with a 9-day history of abdominal cramps, nausea, vomiting, bloody diarrhea, and a pruritic, papular rash over his extremities. Seven days before admission, he was treated empirically with amoxicillin. The rash improved, but 2 days before admission, the patient experienced migratory arthralgias and myalgias and a nonpruritic, purpuric eruption on his extremities. The day before admission, his medication was switched from amoxicillin to erythromycin. A review of his systems revealed no recent upper respiratory tract infections or fevers. On admission, the patient had a low-grade fever (temperature, 41.1°C), a pulse rate of 93/min, and a blood pressure reading of 112/46 mm Hg. A stool sample was guaiac positive. Skin examination revealed palpable purpuric lesions on the lower part of both legs ( Figure 1 ). There was also mild involvement of the forearms, but the palms and