What are the different types of vasculitis and their characteristics?

Vasculitis can have various causes, including infections, drugs, chemicals, and systemic or malignant processes.
The pathogenesis of vasculitis involves an immune reaction type III, with the deposition of circulating immune complexes Ag-Ac in the vascular wall, complement activation, neutrophilic leukocytoclasis, release of lysosomal enzymes, which in turn cause damage to the vessel, and tissue necrosis.
The most common form of vasculitis is vasculitis by hypersensitivity, which includes leukocytoclastic vasculitis, Schönlein-Henoch purpura, urticarial vasculitis, mixed essential cryoglobulinemia, and serum sickness.
Panarteritis nodosa is a necrotizing vasculitis that affects the entire wall of small and medium-sized muscular arteries, segmentally and mainly at the bifurcations.