Small-Vessel Vasculitis

History, Epidemiology

Small-vessel vasculitis is the umbrella name for a group of rare diseases characterized by inflammation of smaller blood vessels, such as arterioles, venules, and capillaries.1 The inflammation can restrict blood flow and damage vital organs and tissues. Some are systemic, while other forms of small-vessel vasculitis only affect the skin.

Each year, about 38 to 55 million adults are diagnosed with cutaneous small-vessel vasculitis.2 It tends to affect females and males equally and is more common in white individuals. Cutaneous small-vessel vasculitis typically occurs in people aged 16 or older.  

Small-vessel vasculitis can be categorized as ANCA-associated or non-ANCA-associated vasculitis. Antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis is the most common type of primary systemic small-vessel vasculitis in adults. The different types of ANCA-associated small-vessel vasculitis include:

  • microscopic polyangiitis
  • Wegener’s granulomatosis
  • Churg-Strauss syndrome
  • drug-induced vasculitis

Non-ANCA small-vessel vasculitis primarily includes Henoch-Schonlein purpura. Henoch-Schonlein purpura is the most common form of small-vessel vasculitis diagnosed in children.3

Precisely what causes small-vessel vasculitis is not fully understood.2 It can be triggered by an allergic reaction to a drug or food, or an infection such as an upper respiratory tract infection or virus (eg, hepatitis B or C, or HIV), and rarely, cancer. The main drugs linked to an increased risk for small-vessel vasculitis include penicillin, cephalosporins, sulfonamides (including most loop and thiazide-type diuretics), phenytoin, and allopurinol.4

Small-Vessel Vasculitis Diagnosis & Presentation

A purple or reddish rash on the legs, buttocks, torso, or upper body is the telltale symptom of small-vessel vasculitis.2

When considering a diagnosis of small-vessel vasculitis, look for palpable purpura (0.3 to 1 cm diameter) and/or petechiae (purpuric lesions less than 3 mm in diameter) that don’t blanch to the touch.4

Patients with small-vessel vasculitis may also present with hives, blisters, open sores, and crops of lesions.2 Other symptoms of small-vessel vasculitis include fever, weight loss, myalgia and arthralgia, kidney involvement, cough, mononeuritis, and gastrointestinal symptoms.3

Most patients develop symptoms around 7 to 10 days after exposure to the responsible drug or infectious agent.4 The initial acute rash of small-vessel vasculitis usually subsides within 2 to 3 weeks, but lesions may recur over weeks and months.

In cases when the inciting agent persists, this condition can become chronic.2 Certain clinical features can help diagnose specific types of small-vessel vasculitis.3 Pulmonary and renal symptoms indicate Wegener’s granulomatosis and microscopic polyangiitis. Sinusitis and otitis media also suggest Wegener’s granulomatosis.

By contrast, pulmonary-dermal symptoms point toward cryoglobulinemia or Henoch-Schonlein purpura, while asthma and eosinophilia are suggestive of Churg-Strauss syndrome.3

Diagnostic Workup

There is no single test that says a patient has small-vessel vasculitis.4 Skin biopsies can provide valuable diagnostic information. Immunofluorescence examination of skin biopsies may show immunoglobulin G (IgG), IgMm, and/or complement deposition with small-vessel vasculitis. The absence of immune complex deposition could, however, be due to late biopsy. This could also indicate an autoimmune type of vasculitis such as microscopic polyangiitis.

If IgA deposition is noted and there is a history of joint or gastrointestinal symptoms, test urine sediment and repeat this test on subsequent visits. Always ask about all current medications the patient is taking as well as a history of recent infection.

Relevant antibody and blood testing during the diagnostic process includes5:

  • antinuclear antibody
  • antineutrophil cytoplasmic antibody
  • hepatitis B and C serologies
  • assessment of complement
  • immunoglobulins
  • complete blood count
  • serum creatinine
  • urinalysis
  • radiographic imaging
  • liver function tests

Imaging studies such as X-rays and computed tomography (CT) scans may help identify direct and indirect signs of vessel inflammation.

A physical examination can help confirm if the disease is limited to skin or systemic in nature. Focus on the joints, gastrointestinal tract, kidneys, lungs, and peripheral and central nervous system.

Ask about previous diagnoses. Small-vessel vasculitis can co-occur with other autoimmune diseases such as rheumatoid arthritis, Crohn’s disease, systemic lupus erythematosus, Sjogren’s syndrome, and larger-vessel vasculitis.4

Differential Diagnosis

The list of potential differential diagnoses with small-vessel vasculitis includes4,6:

  • macular purpura due to coagulation defects
  • inflammatory skin diseases
  • infections
  • lymphoproliferative disease
  • scurvy
  • Ehlers-Danlos syndrome
  • cholesterol emboli
  • actinic and senile purpura
  • glucocorticoid-induced purpura
  • autoimmune thrombocytopenia
  • thrombotic thrombocytopenic purpura

Small-Vessel Vasculitis Management
(Non-pharmacotherapy and pharmacotherapy)

The first step is to address the causative agent. This may require ceasing medication, avoiding the food allergen, or treating underlying infection.5 Some patients will also require corticosteroids in combination with other immunosuppressive medications such as azathioprine and methotrexate. Other potential medications may include colchicine, antihistamines, hydroxychloroquine, and dapsone alone or in combination.

Symptoms of small-vessel vasculitis will often resolve within a few weeks to months if there is no organ involvement.2 Patients should avoid prolonged standing because the legs are commonly affected by rash or joint pain. Elevation of the legs and use of compression stockings are also recommended. Comorbidities such as hypertension, diabetes, hypercholesterolemia, and smoking can accelerate vascular damage and should be adequately treated as well.3

Monitoring Side Effects, Adverse Events, Drug-Drug Interactions

Small-vessel vasculitis patients who primarily have skin and or/joint symptoms have a good prognosis. Some medications used to treat cutaneous small-vessel vasculitis can increase risk of infection and contribute to osteoporosis. Patients on these medications should be monitored. Medications may be prescribed to manage these side effects. In addition, getting the flu shot, pneumonia vaccine, and shingles vaccine can reduce the risk of infection in patients taking immunomodulating drugs.2


  1. Jennette JC, Falk RJ. Small-Vessel Vasculitis. N Engl J Med. 1997; 337:1512-1523. doi: 10.1056/NEJM199711203372106
  1. Cutaneous small-vessel vasculitis. Vasculitis Foundation. Accessed September 12, 2022
  1. Mansi IA, Opran A, Rosner F. ANCA-associated small-vessel vasculitis. Am Fam Physician. 2002;65(8):1615-1621.
  1. Gota C. Overview of cutaneous small vessel vasculitis. UpToDate. Last updated September 16, 2022. Accessed September 20, 2022
  1. Gamarra AI. MattesonEL,  RestrepoJF. Small vessel vasculitis
    history, classification, etiology, histopathology, clinic, diagnosis and treatment
    Rev Colomb Reumatol. 2007;35(3):87-205.
  1. Haemel A, Fox L, Connolly MK. Cutaneous small-vessel vasculitis. In: Oxford Textbook of Vasculitis. 3rd ed. Feb 2014.

Author Bio

Denise Mann, MS, is a veteran freelance health writer in New York. Her work has appeared on HealthDay, among other outlets. She was awarded the 2004 and 2011 journalistic Achievement Awards from the American Society for Aesthetic Plastic Surgery. She was also named the 2011 National Newsmaker of the Year by the Community Anti-Drug Coalitions of America. She has also been awarded the Arthritis Foundation’s Northeast Region Prize for Online Journalism, the Excellence in Women’s Health Research Journalism Award, the Gold Award for Best Service Journalism from the Magazine Association of the Southeast, a Bronze Award from The American Society of Healthcare Publication Editors, and an honorable mention in the International Osteoporosis Foundation Journalism Awards. She was part of the writing team awarded a 2008 Sigma Delta Chi award for her part in a WebMD series on autism. Mann has a graduate degree from the Medill School of Journalism at Northwestern University in Evanston, Ill.