Causes of leukocytoclastic vasculitis

Causes of leukocytoclastic vasculitis (LCV) includeFiorentino, 2003:

• idiopathic (in 50% of cases)
• infection (in 15 to 20% of cases) (eg Streptococcus pyogenes, Neisseria meningitidis, hepatitis B or C virus, upper respiratory tract infection, human immunodeficiency virus [HIV])
• connective tissue disease (in 15 to 20% of cases) (eg systemic lupus erythematosus, rheumatoid arthritis, Sjögren syndrome)
• drugs (in 10 to 15% of cases) (eg antibiotics [beta lactam antibiotics, sulfonamides], allopurinol, nonsteroidal anti-inflammatory drugs [NSAIDs]). The most common cause of drug-induced LCV is antibiotics; onset is typically 7 to 21 days after the first exposure to the drug, or hours to days after rechallenge. See also Cutaneous drug reactions
• malignancy (in less than 5% of cases) (eg plasma cell dyscrasia, myelodysplasia, myeloproliferative and lymphoproliferative disorders).

Exercise-induced vasculitis is not a true vasculitis, but it does mimic the presentation of vasculitis on the lower limbs. It is benign and can be triggered by prolonged walking in hot weather.