For patients · General Rheumatology

ANCA-associated vasculitis

AAV, granulomatosis with polyangiitis, GPA, microscopic polyangiitis, MPA, eosinophilic granulomatosis with polyangiitis, EGPA, Wegener's, Churg-Strauss

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The short versionANCA-associated vasculitis, or AAV, is a group of three related autoimmune diseases that inflame small and medium-sized blood vessels. This inflammation can damage many organs, most often the sinuses, lungs, kidneys, nerves, and skin. The three types are granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). These are serious conditions, but modern treatment has transformed the outlook, and the aim is to bring the disease into remission and keep it there.
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Safety update: avacopan (Tavneos) should not be started in new patients right now

Health Canada issued a safety advisory on 7 July 2026 about avacopan (Tavneos). The main study that supported it, the ADVOCATE trial, was withdrawn (retracted) by the New England Journal of Medicine on 29 June 2026 because some of its results had been changed in a way that was not proper or disclosed, which raises questions about how well the medicine works. Health Canada advises that no new patients should be started on avacopan while it reviews these concerns, and that people already taking it should speak with their care team, not stop on their own. The mentions of avacopan below describe a 2022 guideline recommendation that was based on that now-withdrawn study, and should be read in light of this update.

Understanding this condition

What ANCA-associated vasculitis is

ANCA-associated vasculitis is a group of autoimmune diseases in which the immune system attacks the walls of small and medium blood vessels, causing inflammation that can injure the organs those vessels supply. The name comes from an antibody called ANCA that is often found in the blood. There are three types. GPA and MPA commonly affect the sinuses, lungs, and kidneys. EGPA usually involves asthma and high eosinophils. Before modern medicines these diseases were often fatal, but treatment today can control them well.

Common symptoms

General symptoms can include fever, tiredness, weight loss, and aching joints and muscles. GPA often causes stubborn sinus and nasal problems, nosebleeds or crusting, and lung symptoms. MPA can cause rapidly worsening kidney problems and, sometimes, coughing up blood. EGPA usually starts with asthma and nasal allergy or polyps, and can cause numbness or weakness from nerve involvement. Any of the three can cause skin rashes, kidney inflammation, or nerve damage.

Who gets it

These are rare diseases. In European studies, GPA affects roughly 24 to 157 people per million, MPA roughly 0 to 66 per million, and EGPA roughly 2 to 38 per million. GPA and MPA most often affect adults in middle age and older. Because the diseases are uncommon and can look like other illnesses, diagnosis sometimes takes time.

How it is diagnosed

Diagnosis puts together your symptoms, blood tests for ANCA antibodies, urine and kidney tests, imaging, and often a small tissue sample (biopsy) from an affected organ such as the kidney, lung, sinus, nerve, or skin. There are two main ANCA patterns: one is more common in GPA and one in MPA. In EGPA, only about 4 in 10 people have a detectable ANCA, so the diagnosis leans more on the asthma, high eosinophils, and other features.

What to expect over time

Before modern treatment these diseases were often fatal. Today, most people can reach remission, meaning the disease becomes quiet, and stay there with maintenance treatment. The diseases can relapse, so ongoing follow-up matters. Some people have a single episode, while others have a relapsing course. Treatment itself carries risks, especially infection, which the team works to prevent.

Living with and treating it

The goals of treatment

There are two goals. First, bring the disease into remission, which means the signs and symptoms settle. Second, keep it in remission while using as little steroid as possible. Severe, organ-threatening disease is treated more intensively, while milder disease can often be treated with gentler medicines.

Treatment options

For severe GPA or MPA, rituximab or cyclophosphamide is used with steroids to bring the disease under control, and the steroid is stepped down to a small dose within a few months. (A newer tablet called avacopan was used to reduce how much steroid is needed, but it should not be started in new patients right now, see the safety update above.) Milder GPA or MPA is treated with steroids plus rituximab in the European guideline, or with methotrexate and steroids in the American guideline (your team will explain which fits you). Once in remission, a maintenance medicine such as rituximab keeps it quiet. In EGPA, steroids are central, severe disease uses cyclophosphamide or rituximab, and milder or relapsing disease often uses a biologic called mepolizumab.

Monitoring and check-ups

Follow-up checks how you feel and how your organs, especially your kidneys and lungs, are doing, and watches for treatment side effects. Your team generally does not change your treatment based on an ANCA blood test alone. If you are on rituximab, your antibody levels may be checked, since low levels with repeated infections can need treatment. Steroid side effects, such as bone thinning, are also monitored.

Relapses and how they are treated

A relapse means the disease comes back after a quiet period. Severe relapses are treated by bringing the disease back into remission, usually with rituximab, or by switching medicines depending on what you were already taking. People who are ANCA PR3 positive or who have relapsed before are more likely to relapse, so follow-up is important.

Living well with AAV

Taking your maintenance medicine as prescribed is the most important thing to prevent relapse. Preventing infection matters too: keep up with vaccines your team recommends, and take any medicine given to prevent a lung infection. If you are on steroids, protecting your bones is important. Not smoking, managing asthma and allergies if you have EGPA, and getting support for fatigue and mood all help. Your care often involves several specialists working together.

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Related problems to watch for

AAV can affect the kidneys enough to need dialysis or, later, a transplant, which is possible once the disease is in remission. There is a higher risk of blood clots in the legs or lungs. Treatment raises the risk of infection, and long-term steroids can affect bones and blood sugar. In EGPA, the heart can be involved, which is a serious concern, so a heart scan is recommended when EGPA is diagnosed.

What to expect at your appointment

At a visit, expect detailed questions about your symptoms across many body systems, and an examination of your sinuses, lungs, skin, nerves, and joints. You will likely have blood tests including ANCA, urine tests to check your kidneys, and imaging, and you may be referred for a biopsy. Because AAV can affect several organs, your care may involve a team, which can include your rheumatologist, a kidney or lung specialist, an ENT surgeon, and a specialist nurse or advanced practice provider, working together in whichever model your clinic uses.

Treat to target

AAV does not have a single disease-activity target number. The aim is remission, meaning the signs and symptoms are gone, and then keeping it there while using as little steroid as possible. In GPA and MPA there is a clear steroid target: to step the steroid down to a small daily dose, about 5 mg of prednisolone a day, within about 4 to 5 months. Your team judges disease control from your symptoms and organ tests, not from an ANCA blood test alone.

How treatment is stepped up

  1. 1

    Remission induction: bring the disease under control

    The first job is to settle active disease. For severe GPA or MPA, rituximab or cyclophosphamide is used with steroids, and the steroid is stepped down to a small dose over a few months. Milder GPA or MPA is treated with steroids plus rituximab (European guideline) or methotrexate plus steroids (American guideline). For EGPA, severe disease uses cyclophosphamide or rituximab, and milder disease often uses mepolizumab, always with steroids. (A newer tablet, avacopan, was recommended by the 2022 European guideline to reduce steroid use, but see the safety update at the top of this page: it should not be started in new patients right now.)

  2. 2

    Remission maintenance: keep it quiet

    Once the disease is in remission, a gentler medicine keeps it there. For severe GPA or MPA, rituximab is often preferred, or methotrexate or azathioprine. For EGPA, methotrexate, azathioprine, or mycophenolate is commonly used. Steroids are lowered to the smallest dose that keeps you well.

  3. 3

    Relapse: re-induce remission

    If the disease comes back, the team brings it back under control, usually with rituximab, or by switching medicines depending on what you were taking.

  4. 4

    Refractory disease and add-ons

    If the disease does not respond, the team switches to the other main medicine rather than combining them, and may add an infusion called IVIG for a while. Medicines to prevent a lung infection are used with rituximab or cyclophosphamide. Refractory disease is best managed at a centre with vasculitis expertise.

Medication guides

Plain-language guides to the medicines used for this condition. Each has a patient and a clinician view.

The numbers, in plain terms

about 4 in 10

In EGPA, only about 4 in 10 people have a detectable ANCA antibody, so the diagnosis relies more on the asthma, high eosinophils, and other features.

Living well, beyond the diagnosis

The whole-person side of living with a rheumatic disease, the parts patients tell us matter most. These guides apply across conditions.

iThis page helps you prepare a conversation with your care team. It does not replace individual medical advice. Always confirm your own plan with your rheumatology team.
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