Which is not true of hypersensitivity vasculitis: March 2011

Ans. B: Affects small, medium-sized and larger aeries commonlyMicroscopic polyangitis is a necrotizing vasculitis that generally affects capillaries, as well as aerioles and venules of a size smaller than those involved in polyaeritis nodosa (medium vessel vasculitis); rarely larger aeries may be involvedIt is also called hypersensitivity vasculitis/ leukoclastic vasculitisCutaneous small-vessel vasculitis/Cutaneous leukocytoclastic angiitis/Cutaneous leukocytoclastic vasculitis/ Cutaneous necrotizing venulitis/ Hypersensitivity angiitis.It is inflammation of small blood vessels (usually post-capillary venules in the dermis), characterized by palpable purpura.It is the most common vasculitis seen in clinical practice.Leukocytoclasis refers to the damage caused by nuclear debris from infiltrating neutrophils in and around the vessels.Subtypes of small-vessel vasculitis include:- Henoch-Schonlein purpura- Acute hemorrhagic edema of infancy- Uicarial vasculitis- Cryoglobulinemic vasculitis- Erythema elevatum diutinum- Granuloma faciale