Vasculitis - allergic hypersensitivity

Alternative names
Allergic vasculitis; Cutaneous Leukocytoclastic Vasculitis

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

Causes, incidence, and risk factors
Vasculitis occurs because of inflammation and damage to blood vessels. The inflammation of allergic vasculitis is the result of an allergic reaction to a drug or other foreign agent.


  • skin lesions usually located on legs, buttocks, or trunk  
  • palpable (able to be felt with the fingers) purpura       o multiple papules (small, solid, raised skin areas)       o purpura (bleeding into the skin)  
  • blisters on the skin  
  • urticaria (hives), may last longer than 24 hours  
  • necrotic ulcers (open sores with dead tissue)

Signs and tests
The diagnosis is primarily based on a history of skin lesions that develop after exposure to medications or a foreign substance (antigen) and the pattern of symptoms.

  • The ESR (sed rate) may be elevated.  
  • Skin biopsy shows vasculitis (inflammation of the blood vessels).

Treatment is aimed at reducing the inflammation, allowing the natural healing process to occur. If possible, stop exposure to the causative medication (or other antigen). Aspirin or corticosteroids may be prescribed to reduce inflammation of the blood vessels. (DO NOT give aspirin to children except as advised by the health care provider.) In severe cases, treatment with corticosteroids may be necessary.

Expectations (prognosis)
Allergic vasculitis usually resolves in time.


  • permanent damage to the blood vessels or skin with scarring  
  • vasculitis affecting the internal organs (kidney, bone, and so on)

Calling your health care provider
Call for an appointment with your health care provider if symptoms indicate allergic vasculitis may be present.

Avoid exposure to medications to which there are known allergies.

Johns Hopkins patient information

Last revised: December 3, 2012
by Martin A. Harms, M.D.

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