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What is Which of the following blood vessels is affected in hypersensitivity vasculitis? and explain in detail?
Hypersensitivity vasculitis (HV) encompasses a heterogeneous group of vasculitides associated with hypersensitivity to antigens from infectious agents, drugs, or other exogenous or endogenous sources. It is characterized pathologically by involvement of postcapillary venules and inflammation and fibrinoid necrosis (necrotizing vasculitis). Clinically, skin involvement is characteristic, manifested by "palpable purpura." Systemic vascular involvement occurs, chiefly in the kidney, muscles, joints, GI tract, and peripheral nerves. Ref: Suurmond D. (2009). Section 14. The Skin in Immune, Autoimmune, and Rheumatic Disorders. In D. Suurmond (Ed), Fitzpatrick's Color Atlas & Synopsis of Clinical Dermatology, 6e.