DefinitionAllergic vasculitis is an extreme reaction to a drug, infection, or foreign substance that leads to inflammation and damage to blood vessels of the skin.
Alternative NamesVasculitis - allergic; Hypersensitivity vasculitis; Cutaneous leukocytoclastic vasculitis
Causes, incidence, and risk factorsAllergic vasculitis is caused by an allergic reaction to a drug or other foreign substance. Most patients are older than 15 years.Even with a thorough history, the cause of this condition cannot be identified.
SymptomsPurple-colored spots and patchesSkin lesions usually located on the legs, buttocks, or trunkBlisters on the skinHives (urticaria), may last longer than 24 hoursOpen sores with dead tissue (necrotic ulcers)
Signs and testsThe diagnosis is based on your symptoms and how the skin looks after you take a certain medicine or are exposed to a foreign substance (antigen).Results from an ESR test may be high. Skin biopsy shows inflammation of the blood vessels.
TreatmentThe goal of treatment is to reduce inflammation.Your health care provider may prescribe aspirin or corticosteroids to reduce inflammation of the blood vessels. (DO NOT give aspirin to children except as advised by your health care provider.)If possible, your doctor may tell you to stop taking the medicine that caused this condition. Do not stop taking any medicine without first talking to your doctor.
Expectations (prognosis)Allergic vasculitis usually goes away over time. On occasion, people will have repeated episodes.
ComplicationsPermanent damage to the blood vessels or skin with scarringInflammation of the blood vessels affects the internal organs
Calling your health care providerCall for an appointment with your health care provider if you have symptoms of allergic vasculitis.
PreventionAvoid exposure to medications to which you have known allergies.
ReferencesStone JH. Immune complex-mediated small vessel vasculitis. In: Firestein GS, Budd RC, Harris Jr. ED, McInnes IB, Ruddy S, eds. Kelley's Textbook of Rheumatology. 8th ed. Philadelphia, Pa: W.B. Saunders Company; 2008: chap 85.