A 74-year-old man with a history of vitamin B12 deficiency and alcoholism presented with a 2-week history of increasing fatigue associated with difficulty in ambulating because of swelling and pain in his left foot and ankle. Over the ensuing 1½ weeks, his foot and ankle became more tender, swollen, and erythematous, and on follow-up examination he was noted to have palpable purpura of both legs.
The findings of laboratory evaluation were remarkable for normocytic anemia (hematocrit, 29.1% [reference range (RR), 40%-52%]); mild renal insufficiency (serum urea nitrogen, 27 mg/dL [9.6 mmol/L] [RR, 6-20 mg/dL (2.1-7.1 mmol/L)]; creatinine, 1.3 mg/dL [115 µmol/L] [RR, 0-1.3 mg/dL (0-115 µmol/L)]) with hematuria and an elevated erythrocyte sedimentation rate (53 mm/h [RR, 0-15 mm/h]). The results of other laboratory studies, including liver function tests, electrolyte levels, white blood cell count with differential cell count, platelet count, prothrombin time, and partial thromboplastin time, were all normal. Also, a Doppler ultrasound study of the left lower extremity failed to reveal the presence of a deep venous thrombosis. No specific diagnosis or treatment was made, and the patient was sent home with close follow-up.
Chartier TK, Johnson RA, Kaminer M, Tahan S. Palpable Purpura in an Elderly Man—Quiz Case. Arch Dermatol. 2003;139(10):1363-1368. doi:10.1001/archderm.139.10.1363-a