Lower limb swelling and r...

A 7-month-old boy presented with a 1-day history of periauricular and lower limb swelling plus rash. He had been refusing to weight bear and had high temperature. Numerous macules were noted over the limbs, face, but his trunk was spared. The lesions were 1–2 cm well-circumscribed purpura, which varied from red to brown. His lower limbs showed signs of oedema. He was systemically well. The child had been exposed to chickenpox. Blood results showed a mildly raised WCC and a C-reactive protein (CRP) of 68. In the following week, he developed a vesicular rash.