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Hypersensitivity vasculitis

Show Alternative Names
Cutaneous small vessel vasculitis
Allergic vasculitis
Leukocytoclastic vasculitis

Hypersensitivity vasculitis is an extreme reaction to a medicine, infection, or foreign substance. It leads to inflammation and damage to blood vessels, mainly in the skin. The term is not used much currently because more specific names are considered more precise.

Causes

Hypersensitivity vasculitis, or cutaneous small vessel vasculitis, is caused by:

  • An allergic reaction to a medicine or other foreign substance
  • A reaction to an infection

It usually affects people older than age 16.

Often, the cause of the problem cannot be found even with a careful study of the person's medical history.

Hypersensitivity vasculitis may look like systemic, necrotizing vasculitis, which can affect blood vessels throughout the body and not just in the skin. In children, it can look like Henoch-Schonlein purpura.

Symptoms

Symptoms may include:

  • New rash with tender, purple or brownish-red spots over large areas
  • Skin sores mostly located on the legs, buttocks, or trunk
  • Blisters on the skin
  • Hives (urticaria), may last longer than 24 hours
  • Open sores with dead tissue (necrotic ulcers)

Exams and Tests

The health care provider will base the diagnosis on symptoms. The provider will review any medicines or drugs you have taken and recent infections. You will be asked about cough, fever, or chest pain.

A complete physical exam will be done.

Blood and urine tests may be done to look for systemic disorders such systemic lupus erythematosus, dermatomyositis, or hepatitis C. The blood tests may include:

Skin biopsy shows inflammation of the small blood vessels.

Treatment

The goal of treatment is to reduce inflammation.

Your provider may prescribe aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), or corticosteroids to reduce inflammation of the blood vessels. (Do not give aspirin to children except as advised by your provider).

Your provider will tell you to stop taking medicines that could be causing this condition.

Outlook (Prognosis)

Hypersensitivity vasculitis most often goes away over time. The condition may come back in some people.

People with ongoing vasculitis should be checked for systemic vasculitis.

Possible Complications

Complications may include:

  • Lasting damage to the blood vessels or skin with scarring
  • Inflamed blood vessels affecting the internal organs

When to Contact a Medical Professional

Contact your provider if you have symptoms of hypersensitivity vasculitis.

Prevention

Do not take medicines that have caused an allergic reaction in the past.

Review Date: 4/1/2025

Reviewed By

Diane M. Horowitz, MD, Rheumatology and Internal Medicine, Northwell Health, Great Neck, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

References

Dinulos JGH. Hypersensitivity syndromes and vasculitis. In: Dinulos JGH, ed. Habif's Clinical Dermatology. 7th ed. Philadelphia, PA: Elsevier; 2021:chap 18.

Stone JH. The systemic vasculitides. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 249.

Stone JH. Immune complex–mediated small vessel vasculitis. In: Firestein GS, McInnes IB, Koretzky GA, Mikuls TR, Neogi T, O'Dell JR, eds. Firestein & Kelley's Textbook of Rheumatology. 12th ed. Philadelphia, PA: Elsevier; 2025:chap 92.

Sunderkötter CH, Zelger B, Chen KR, et al. Nomenclature of cutaneous vasculitis: dermatologic addendum to the 2012 revised International Chapel Hill Consensus Conference Nomenclature of vasculitides. Arthritis Rheumatol. 2018;70(2):171-184. PMID: 29136340 pubmed.ncbi.nlm.nih.gov/29136340/.

Disclaimer

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

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Images
Vasculitis on the palm - Illustration Thumbnail

Vasculitis on the palm

These spots of blood under the skin, called purpura, are caused by vasculitis. They do not turn white with pressure (non-blanchable). In this particular case, the purpura are associated with an underlying disorder affecting the structure of the blood vessel walls called collagen-vascular disorder.

Illustration

Vasculitis - Illustration Thumbnail

Vasculitis

Inflammation of the blood vessels (vasculitis) may be caused when antibodies that have attached to antigens in the blood (immune complexes), attach to the blood vessel walls. These purplish spots can be felt in the skin. They do not turn white (blanch) when pressed. As the condition progresses, they may become larger and more bruise-like (ecchymotic), and some may develop central ulceration or necrosis (tissue death).

Illustration

Vasculitis - urticarial on the hand - Illustration Thumbnail

Vasculitis - urticarial on the hand

These red (erythematous), hive-like (urticarial) spots (plaques) are caused by inflammation of the blood vessels (urticarial vasculitis) and do not change over a 24-hour period. They may or may not turn white (blanch) with pressure.

Illustration

 
 
Vasculitis on the palm - Illustration Thumbnail

Vasculitis on the palm

These spots of blood under the skin, called purpura, are caused by vasculitis. They do not turn white with pressure (non-blanchable). In this particular case, the purpura are associated with an underlying disorder affecting the structure of the blood vessel walls called collagen-vascular disorder.

Illustration

Vasculitis - Illustration Thumbnail

Vasculitis

Inflammation of the blood vessels (vasculitis) may be caused when antibodies that have attached to antigens in the blood (immune complexes), attach to the blood vessel walls. These purplish spots can be felt in the skin. They do not turn white (blanch) when pressed. As the condition progresses, they may become larger and more bruise-like (ecchymotic), and some may develop central ulceration or necrosis (tissue death).

Illustration

Vasculitis - urticarial on the hand - Illustration Thumbnail

Vasculitis - urticarial on the hand

These red (erythematous), hive-like (urticarial) spots (plaques) are caused by inflammation of the blood vessels (urticarial vasculitis) and do not change over a 24-hour period. They may or may not turn white (blanch) with pressure.

Illustration

 
 
 
 
 
 

 

 
 
 
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