Drugs most commonly implicated are penicillin, sulphonamides and thiazide diuretics. Methamphetamine and other sympathomimetics can cause a cerebral vasculitis alongside polyarteritis nodosa like systemic features. With other drugs,there is presence of skin vasculitis with palpable petechiae or purpura. Biopsy of these lesions reveal inflammation of the small vessels, termed leukocytoclastic vasculitis, which is most prominent in postcapillary venules. At least three out of five criteria yields sensitivity and specificity of 71 and 84%:

Age > 16
Use of possible triggering drug in relation to symptoms
Palpable purpura
Maculopapular rash
Skin biopsy showing neutrophils around vesselIgA vasculitis (formerly known as Henoch–Schonlein purpura). Systemic vasculitis due to tissue deposition of IgA-containing immune complexes. Biopsy of lesions shows inflammation of small vessels. It is considered a form of hypersensitivity vasculitis but is distinguished by prominent deposits of IgA. This is the most common vasculitis in children. Presence of three or more criteria yielded sensitivity of 87% while less than two criteria yielded hypersensitivity vasculitis in 74%:

Palpable purpura (usually of buttocks and legs)
Bowel angina
GI bleed
Hematuria
Onset < 20 years
No new medicationsEssential cryoglobulinemic vasculitis. Most often due to hepatitis C infection, immune complexes of cryoglobulins – proteins that consists of immunoglobulins and complement and precipitate in the cold while dissolving upon rewarming – are deposited in walls of capillaries, venules, or arterioles. Therefore, complement will be low with histology showing vessel inflammation with immune deposits. Other/ungrouped
Vasculitis secondary to connective tissue disorders. Usually secondary to systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), relapsing polychondritis, Behçets disease, and other connective tissue disorders. Vasculitis secondary to viral infection.
Necrotizing vasculitis, also called systemic necrotizing vasculitus, is a category of vasculitis, comprising vasculitides that present with necrosis.Examples include giant cell arteritis, microscopic polyangiitis, and granulomatosis with polyangiitis. ICD-10 uses the variant "necrotizing vasculopathy". ICD-9, while classifying these conditions together, does not use a dedicated phrase, instead calling them "polyarteritis nodosa and allied conditions". When using the influential classification known as the "Chapel Hill Consensus Conference", the terms "systemic vasculitis" or "primary systemic vasculitides" are commonly used. Although the word necrotizing is omitted, the conditions described are largely the same. Classification
Large vessel vasculitis
Giant-cell arteritis and Takayasus arteritis have much in common, but usually affect patients of different ages, with Takayasus arteritis affecting younger people, and giant-cell arteritis having a later age of onset. Aortitis can also be considered a large-vessel disease.Takayasu arteritis. Primarily affects the aorta and its main branches. At least three out of six criteria yields sensitivity and specificity of 90.5 and 97.8%:

Onset < 40 years affects young and middle -aged women (ages 15–45)
Claudication of extremities
Decreased pulsation of one or both brachial arteries
At least 10 mmHg systolic difference in both arms
Bruit over one or both carotid arteries or abdominal aorta
Arteriographic narrowing of aorta, its primary branches, or large arteries in upper or lower extremities
Ocular manifestation
Visual loss or field defects
Retinal hemorrhages
Neurological abnormalities
Treatment: steroidsGiant cell (temporal) arteritis. Chronic vasculitis of both large and medium vessels, primarily affecting cranial branches of the arteries arising from the aortic arch.