Abstract:
Vasculitis syndromes are classified, according to the size of
the affected vessels, into large-vessel, medium-vessel, and
small-vessel vasculitis (Table 1). Large-sized vessel vasculitis,
ie, vasculitis occurring in the aorta and its major
branches to the extremities, the head and the neck, includes
Takayasu arteritis and temporal arteritis. Medium-sized vessel
vasculitis, ie, vasculitis occurring in the major arteries
and their branches to the visceral organs, includes polyarteritis
nodosa (PAN), Kawasaki disease, and Buerger disease.
Small-sized vessel vasculitis occurs in the arterioles, capillaries,
and venules. In some cases, small arteries are also
affected. Small-sized vessel vasculitis is classified according
to the involvement of immune complexes. Vasculitis involving
immune complexes include Henoch-Schönlein purpura,
essential cryoglobulinemia, and malignant rheumatoid
arthritis (MRA) (rheumatoid vasculitis). Small-sized vessel
vasculitis not involving immune complexes include microscopic
polyangiitis (MPA), Wegener’s granulomatosis, and
allergic granulomatous angiitis. Since these three conditions
are associated with the presence of marker antibodies, ie
