Henoch-Schönlein purpura (IgA vasculitis) most commonly involves which vessel calibre and immunoreactant?

• A Large vessel; IgG
• B Medium vessel; ANCA
• C Arterioles; complement C3 only
• D Small vessel (postcapillary venules); IgA ✓

Explanation

HSP (IgA vasculitis) is a small-vessel vasculitis characterised by deposition of IgA1-dominant immune complexes in postcapillary venules. This results in palpable purpura (non-blanchable) predominantly on the lower extremities, arthritis, abdominal pain and glomerulonephritis. Histology shows leukocytoclastic vasculitis; DIF reveals IgA in vessel walls. ANCA-associated vasculitides (GPA, EGPA, MPA) are small-to-medium vessel disorders but are pauci-immune.

Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.