National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Microscopic polyangiitis

Microscopic polyangiitis (MPA) is a disorder that causes blood vessel inflammation (vasculitis), which can lead to organ damage.[1] The kidneys, lungs, nerves, skin, and joints are the most commonly affected areas of the body. MPA is diagnosed in people of all ages, all ethnicities, and both genders.[2] The cause of this disorder is unknown.
Last updated: 8/13/2014
The symptoms of MPA depend on which blood vessels are involved and what organs in the body are affected. The most common symptoms of MPA include kidney inflammation, weight loss, skin lesions, nerve damage, and fevers.[2] Other symptoms depending on the area(s) of the body affected may include:[3]
  • Skin-Rash
  • Lungs-cough, breathing problems, spitting up blood
  • Gastrointestinal-bleeding in the gastrointestinal tract, abdominal pain
  • Brain/neurological-tingling, pain, weakness, loss of sensation, seizures
  • Musculoskeletal-joint pain, muscle pain
Last updated: 7/6/2016

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Showing of 35 |
Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Autoimmunity
Autoimmune disease
Autoimmune disorder
[ more ] 		0002960
Erythema 0010783
Fever 0001945
Glomerulopathy 0100820
Hematuria
Blood in urine
0000790
Hemoptysis
Coughing up blood
0002105
Oliguria 0100520
Renal insufficiency
Renal failure
Renal failure in adulthood
[ more ] 		0000083
Skin rash 0000988
Vasculitis
Inflammation of blood vessel
0002633
30%-79% of people have these symptoms
Abdominal pain
Pain in stomach
Stomach pain
[ more ] 		0002027
Arthralgia
Joint pain
0002829
Diarrhea
Watery stool
0002014
Gastrointestinal hemorrhage
Gastrointestinal bleeding
0002239
Gastrointestinal infarctions
Death of digestive organ tissue due to poor blood supply
0005244
Myalgia
Muscle ache
Muscle pain
[ more ] 		0003326
Nausea and vomiting 0002017
Peritonitis 0002586
Skin ulcer
Open skin sore
0200042
Subcutaneous hemorrhage
Bleeding below the skin
0001933
Venous thrombosis
Blood clot in vein
0004936
5%-29% of people have these symptoms
Abnormal retinal vascular morphology
Abnormality of retina blood vessels
0008046
Arrhythmia
Abnormal heart rate
Heart rhythm disorders
Irregular heart beat
Irregular heartbeat
[ more ] 		0011675
Arthritis
Joint inflammation
0001369
Congestive heart failure
Cardiac failure
Cardiac failures
Heart failure
[ more ] 		0001635
Cutis marmorata 0000965
Episcleritis
Inflammation of the thin layer on top of the white part of eye
0100534
Epistaxis
Bloody nose
Frequent nosebleeds
Nose bleed
Nose bleeding
Nosebleed
[ more ] 		0000421
Gangrene
Death of body tissue due to lack of blood flow or infection
0100758
Pancreatitis
Pancreatic inflammation
0001733
Paresthesia
Pins and needles feeling
Tingling
[ more ] 		0003401
Pericarditis
Swelling or irritation of membrane around heart
0001701
Sinusitis
Sinus inflammation
0000246
Subcutaneous nodule
Firm lump under the skin
Growth of abnormal tissue under the skin
[ more ] 		0001482
Uveitis 0000554
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Last updated: 7/1/2020
The cause of MPA is unknown. It is not contagious, does not usually run in families, and is not a form of cancer. The immune system is thought to play a critical role in the development of MPA.  It is thought that the immune system becomes overactive and causes blood vessel and tissue inflammation, which leads to organ damage. It is not known what causes the immune system to become overactive.[1]
Last updated: 8/13/2014
The treatment of MPA is dependent on the extent of the disease, rate of progression, and the degree of inflammation. The goal of treatment is to stop organ damage that occurs as a result of MPA and involves use of medications that suppress the immune system. Treatment is typically carried out in three phases:[1][2][3]
  1. Remission induction using prednisone and cyclophosphamide. This phase usually lasts between 4 and 6 months. 
  2. Remission maintenance using prednisone and replacing cyclophosphamide with other medications such as methotrexate and azathioprine. This phases usually lasts between 12 and 24 months. 
  3. Treatment of relapse utilizing medications from phase one or other therapies such as intravenous immunoglobulin for resistant cases. 

Last updated: 7/6/2016

FDA-Approved Treatments

The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition. Learn more orphan products.

The prognosis for MPA depends on the severity of the condition. Early diagnosis and prompt treatment lead to a better overall prognosis.[1] With treatment, 75 percent of individuals achieve complete remission.[3] After achieving remission, it is possible for MPA to recur (often referred to as a “relapse”). Relapses occur in about 30-50% of people with MPA. Achieving remission is again possible for most people with MPA.[1][3]
Last updated: 7/6/2016

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

  • If your physician would like to review your case with a vasculitis specialist, the Vasculitis Foundation lists vasculitis medical consultants that may be able to speak with your healthcare provider. Click on the link above to learn more.
  • The Vasculitis Foundation has a "Find a Physician" map on its website.

Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.

Conditions with similar signs and symptoms from Orphanet
The differential diagnosis includes Wegener's granulomatosis and Churg-Strauss syndrome (distinguished from MPA by the presence of necrotizing granulomatous inflammation in the absence or presence of asthma, respectively), and Henoch-Schönlein purpura and cryoglobulinemic vasculitis (distinguished from MPA by IgA-dominant and cryoglobulin immune deposits, respectively) (see these terms).
Visit the Orphanet disease page for more information.

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • ClinicalTrials.gov lists trials that are related to Microscopic polyangiitis. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.

Patient Registry

  • The Autoimmune Registry supports research for Microscopic polyangiitis by collecting information about patients with this and other autoimmune diseases. You can join the registry to share your information with researchers and receive updates about participating in new research studies. Learn more about registries.
  • The Vasculitis Clinical Research Consortium (VCRC) is an integrated group of academic medical centers, patient support organizations, and clinical research resources dedicated to conducting clinical research in different forms of vasculitis. The VCRC has a contact registry for patients who wish to be contacted about clinical research opportunities and updates on the progress of the VCRC research projects.

    For more information on the registry see: https://www.rarediseasesnetwork.org/cms/vcrc/About-Us

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

Organizations Providing General Support

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
  • The Johns Hopkins Vasculitis Center Web site has an information page on microscopic polyangiitis.  Click on the Johns Hopkins link to view this information.
  • The Vasculitis Foundation has an information page on microscopic polyangiitis on their Web site.  Click on the Vasculitis Foundation link to view this information.
  • The National Institute of Neurological Disorders and Stroke (NINDS) collects and disseminates research information related to neurological disorders. Click on the link to view information on this topic.
  • The Cleveland Clinic Web site has an information page on Microscopic polyangiitis. Click on the Cleveland Clinic link to view this page.

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Microscopic polyangiitis. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know. Submit a new question

  • A member of my family has microscopic polyangiitis. What can you tell me about this condition? See answer

  • My 12-year-old son was recently diagnosed with microscopic polyangiitis, presenting with acute renal failure. I need information regarding cause, treatment, and prognosis. I am specifically interested in information on pediatric cases of this disorder. See answer


  1. Microscopic Polyangiitis. Cleveland Clinic Web site. 2/27/2014; http://my.clevelandclinic.org/health/diseases_conditions/hic_Microscopic_Polyangitis.
  2. Microscopic polyangiitis. The Johns Hopkins Vasculitis Center Web site. 2014; http://www.hopkinsvasculitis.org/types-vasculitis/microscopic-polyangiitis/.
  3. Farid-Moayer M. Microscopic polyangiitis. Medscape. December 21, 2014; http://emedicine.medscape.com/article/334024-overview.