skip to main content

IgA Vasculitis — SCE Rheumatology MCQ

Instant feedback + full explanation. One question, done properly.

HardVasculitisIgA VasculitisSCE Rheumatology

A 45-year-old woman develops a painful, asymmetric axonal neuropathy causing left foot drop and right wrist drop. She also has non-thrombocytopenic palpable purpura over both lower legs. Skin biopsy demonstrates leucocytoclastic small-vessel vasculitis with dominant vascular IgA deposition on direct immunofluorescence. Her eosinophil count and C4 concentration are normal; ANCA and serum cryoglobulins are negative. Urinalysis and estimated glomerular filtration rate are normal. What is the most likely unifying diagnosis?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: C — IgA vasculitis

The diagnosis is **IgA vasculitis**. The decisive finding is leucocytoclastic small-vessel vasculitis with dominant vascular IgA deposition in a patient with palpable purpura. Renal disease is common in adult IgA vasculitis but is not required. Mononeuritis multiplex is unusual but recognised and accounts for the asymmetric wrist and foot drops. Cryoglobulinaemic vasculitis can cause purpura and neuropathy, but negative cryoglobulins, normal C4 and IgA-dominant vascular deposition argue against it. EGPA would usually require asthma, eosinophilia or another eosinophilic feature; ANCA may be negative and is therefore not the sole discriminator. PAN causes a necrotising medium-vessel vasculitis rather than IgA-dominant leucocytoclastic vasculitis. Systemic neuropathy also excludes skin-limited cutaneous vasculitis.

Reference: Bayindir Y, Grayson PC, Gribbons KB, et al. Performance in adults of the EULAR/PRINTO/PRES (Ankara 2008) classification criteria for IgA vasculitis. RMD Open. 2025;11:e005728. https://pubmed.ncbi.nlm.nih.gov/40695543/