Which of the pa of the vascular system is affected in hypersensitivity vasculitis?

Hypersensitivity vasculitis (HV) or allergic cutaneous vasculitis or necrotizing vasculitis 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." Schonlein-Henoch purpura is a type of HV associated with IgA deposits in skin. 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.