A Purpuric Rash

Abstract

A 48-year-old man had erythema without warmth over his right ankle and dorsomedial foot, with nontender, nonpalpable purpura over the foot dorsum and scattered petechiae over the right lower leg 6 weeks after immobilization for an ankle fracture; temperature was 38.2°C (100.8°F) and the erythema faded when he elevated his leg above heart level. What is the diagnosis and what would you do next?

Purpura due to deep venous thrombosis

“…Features of purpura in this case suggest a congestion of the anterior accessory great saphenous vein, which drains into the femoral vein 2 . Given that purpura is an unusual presentation of deep vein thrombosis, 1,3 in addition to venous occlusion by thrombosis, locally incompetent valves and a weakened venous wall, particularly in older women, 4 might cause purpura at the proximal lower limb.…”

“…Purpura is a clinical manifestation of blood extravasation into the mucosa or skin due to vessel wall damage, vascular occlusion, or coagulopathy 1 . Features of purpura in this case suggest a congestion of the anterior accessory great saphenous vein, which drains into the femoral vein 2 .…”