Hypersensitivity / Leukocytoclastic Vasculitis

• Leukocytoclastic vasculitis (LCV) is pathology term for an inflammatory disorder affecting small blood vessels of the skin (also known as hypersensitivity vasculitis)
• Typically presents as red or violaceous papules, otherwise known as palpable purpura: lesions are papular because the overlying skin is stretched and expanded by an intense vasocentric infiltrate, the erythema (or “purpuric”) component of LCV is due to the extravasated erythrocytes
• LCV can develop at any site but is usually distributed on the lower extremities or in dependent areas 
• In addition to palpable purpura, LCV can present as vesicopustules, necrotic papules, and ulcers
• LCV can exist in its own (idiopathic), but is often associated with an underlying systemic disease.  Most common precipitants include medications or infection.  Other causes include: connective tissue diseases or systemic vasculitides, cryoglobulinemia, Hep B or C infection or underlying malignancy. 
• In children LCV is often associated with HSP

(Victoria Kelly MD, 12/7/10)