Case presentation A 50-year-old female without prior medical history presented with a two-days old bilateral palpable purpuric rash on her lower limbs (Cover image 1). It started around the ankles and then spread proximally to the thighs, not extending above the waist.
Lab investigations Normal complete blood count and renal function C4 level: 0.04 g/L (reference range 0.16–0.52 g/L) C3 level: Normal value Mildly elevated rheumatoid factor: 20 kU/L (reference range <14 kU/L) CRP: 5.6 mg/L (reference range <5.0 mg/L) ESR: 26 mm/h (reference range 1–15 mm/h) Low levels of cryoglobulin: 1+ Negative results for antinuclear antibodies, antineutrophil cytoplasmic antibodies, anti-hepatitis C antibodies, and hepatitis B surface antigen Skin biopsy (epidermis, dermis, and a narrow rim of subcutis) Leucocytoclastic vasculitis, including the upper dermal small vessels (Cover image 2) A…
