HSP, also known as anaphylactoid purpura and immunoglobulin A (IgA) vasculitis, is a small-vessel leukocytoclastic vasculitis characterized by the perivascular deposition of IgAl-based immune complexes in the walls of arterioles and postcapillary venules
mature, non-activated) lymphocytes migrate from the peripheral blood into lymph nodes and Peyer's patches by selectively interacting with the specialized endothelium of postcapillary venules
called high endothelial venules (HEVs).
A postulated mechanism for necrotizing vasculitis in hepatitis C virus infection is a deposition of circulating immune complexes in postcapillary venules
It could be due to the endothelial cell edema in the endothelium of postcapillary venules
which cause obstruction in the blood flow and reduction in oxygen transport (Oliveira et al.
vasodilator of postcapillary venules
which cause increased vascular permeability in postcapillary venules
, leading to protein extravasation (tissue edema)
Together, the arterioles, associated capillary network, and postcapillary venules
form a functional unit called the microcirculatory or microvascular bed of that tissue.
The first reports of eczematous inflammation within congenital malformations of postcapillary venules
appeared in the mid-1990s with descriptions of dermatitis within nuchal-occipital port wine stains (PWS) in children (1, 2).
The interaction between neutrophils and vascular endothelium is a key step in the inflammatory process, which usually takes place in postcapillary venules
It involves the small blood vessels and postcapillary venules
Increased permeability results mainly from actions of histamine on postcapillary venules
, where histamine causes the endothelial cells to contract and separate at their boundaries (Goodman-Gilman 1990).
This swelling condition is a result of interstitial edema from vasoactive mediators increasing the permeability of postcapillary venules
of the subcutaneous and submucosal tissues.
In Type III reaction, complexes formed by the drug or its metabolite and specific IgG and IgM antibodies developed against these are deposited in postcapillary venules