A 7-year-old boy has colicky abdominal pain, palpable purpura over the buttocks and legs, arthralgias, and hematuria. Skin biopsy shows leukocytoclastic vasculitis of small vessels. Direct immunofluorescence of the biopsy will demonstrate:

• A Granular IgG and C3 in a full house pattern
• B Linear IgG deposition along the basement membrane
• C Pauci-immune staining with perinuclear ANCA positivity
• D Granular IgA and C3 deposition in vessel walls ✓

Explanation

Henoch-Schonlein purpura, now called IgA vasculitis, is a small-vessel leukocytoclastic vasculitis driven by IgA-containing immune complex deposition in vessel walls, demonstrable as granular IgA and C3 on direct immunofluorescence. It classically follows an upper respiratory infection in children and involves skin, gut, joints, and kidneys. Linear IgG defines anti-GBM disease and full house deposits define lupus, both of which are immunofluorescence patterns incompatible with this diagnosis.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.