Table 1.

Classification and causes of leukocytoclastic vasculitis

CHCC 2012 category	Causes and/or associated diseases	CHCC 2012 definition	Histopathology
ANCA-associated vasculitis	Granulomatosis with polyangiitis (GPA) Microscopic polyangiitis (MPA) Eosinophilic granulomatosis with polyangiitis (EGPA)	Necrotizing vasculitis with few or no immune deposits, predominantly affecting small vessels (i.e., capillaries, venules, arterioles, and small arteries); associated with ANCAs	Vasculitis of small-to-medium vessels in the skin, often with leukocytoclasia with or without granulomatous inflammation
Immune complex vasculitis		Vasculitis with moderate-to-marked vessel wall deposits of immunoglobulin and/or complement components, predominantly affecting small vessels (i.e., capillaries, venules, arterioles, and small arteries)	LCV of small vessels (mostly postcapillary venules, occasionally small veins or arterioles)
	Cryoglobulinemic Vasculitis (CV)	Vasculitis with cryoglobulin immune deposits affecting small vessels (predominantly capillaries, venules, or arterioles); associated with serum cryoglobulins	LCV of small vessels (postcapillary venules, small veins, or arterioles); associated with serum cryoglobulins (usually type II and type III)
	IgA-Vasculitis (Henoch–Schonlein purpura, HSP)	Vasculitis with IgA1-dominant immune deposits, affecting small vessels (predominantly capillaries, venules, or arterioles)	Leukocytoclastic IgA1-dominant vasculitis of mostly postcapillary venules and also veins or arterioles in the skin, with vascular IgA deposits
	Hypocomplementemic Urticarial Vasculitis (anti-C1q vasculitis, HUV)	Vasculitis accompanied by urticaria and hypocomplementemia, affecting small vessels (i.e., capillaries, venules, or arterioles) and associated with anti-C1q antibodies; common forms include glomerulonephritis, arthritis, obstructive pulmonary disease, and ocular inflammation	Cutaneous LCV of mostly postcapillary venules with vascular deposits of immunoglobulins, and manifesting with lasting urticarial lesions; anti C1q antibodies may be present
	IgM/IgG immune complex vasculitis*	Vasculitis with IgM and/or IgG-dominant immune deposits, affecting small vessels (predominantly capillaries, venules, or arterioles)	Leukocytoclastic IgM and/or IgG-dominant vasculitis of mostly postcapillary venules and also veins or arterioles in the skin, with vascular deposits
Vasculitis associated with systemic diseases	Rheumatoid arthritis Systemic lupus erythematosus Sjögren syndrome Sarcoidosis	Vasculitis that is associated with and maybe secondary to (caused by) a systemic disease (e.g., rheumatoid vasculitis, SLE, sarcoid vasculitis, etc.); the name (diagnosis) should have a prefix term specifying the systemic disease (e.g., rheumatoid vasculitis, lupus vasculitis, etc.)	Cutaneous LCV as a component of systemic vasculitis; the type of cutaneous vasculitis (small vessel or medium vessel vasculitis) varies depending on the underlying systemic disease
Vasculitis associated with probable etiology	Drugs Infection Sepsis Neoplasms	Vasculitis that is associated with a probable specific etiology, e.g., drug, infection, sepsis, neoplasm, etc	Cutaneous LCV as a component of systemic vasculitis that is associated with a probable specific etiology, e.g., drug, sepsis, etc

^*Provisional category not included in the CHCC 2012