Allergic vasculitis is hypersensitivity to a drug or foreign substance that leads to inflammation and damage to blood vessels of the skin.

Vasculitis - allergic hypersensitivity; Cutaneous leukocytoclastic vasculitis

Allergic vasculitis is caused by an allergic reaction to a drug or other foreign substance.

• Skin lesions usually located on legs, buttocks, or trunk
• Purpura
• Blisters on the skin
• Urticaria (hives), may last longer than 24 hours
• Necrotic ulcers (open sores with dead tissue)

The diagnosis is primarily based on your sysmptoms and how the skin looks after you take a certain medicine or are exposed to a foreign substance (antigen).

Results from an ESR (sed rate) test may be high. Skin biopsy shows inflammation of the blood vessels.