Caring for someone with this diagnosis? Eleplan keeps diagnoses, medications, documents and every specialist in one plan.
Start free with EleplanMicroscopic polyangiitis
ORPHA:727Disease
Also called MPA · Micropolyangiitis · Microscopic polyarteritis
What it is
A rare inflammatory, necrotizing, systemic vasculitis that affects predominantly small vessels (i.e. small arteries, arterioles, capillaries, venules) in multiple organs, including the kidney, the lungs, the skin and the peripheral nerves.
Key facts
- Prevalence
- 1-9 / 100 000
- Age of onset
- Adult, Childhood
- Inheritance
- Not applicable
- Classified as
- Disease
Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.
Signs and symptoms
Very common80–99%
13Common30–79%
22- Abdominal pain
- Abnormal urine cytology
- Anemia
- Anti-myeloperoxidase antibody positivity
- Anti-neutrophil elastase antibody positivity
- Anti-proteinase 3 antibody positivity
- Arthralgia
- Cytoplasmic antineutrophil antibody positivity
- Diarrhea
- Elevated erythrocyte sedimentation rate
- Fatigue
- Gastrointestinal hemorrhage
- Gastrointestinal infarctions
- Livedo reticularis
- Multiple mononeuropathy
- Myalgia
- Nausea and vomiting
- Peritonitis
- Poor appetite
- Skin ulcer
- Subcutaneous hemorrhage
- Venous thrombosis
Sometimes5–29%
20- Abnormal retinal vascular morphology
- Arrhythmia
- Arthritis
- Chest pain
- Congestive heart failure
- Cutis marmorata
- Diffuse alveolar hemorrhage
- Episcleritis
and 12 more in this range
These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.
ICD-10 codes
Related health topics
Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.
Cross-references
Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.
Powered by Eleplan
A rare diagnosis is just the start. Eleplan keeps the whole care plan in one place.
Diagnoses, medications, documents, appointments, and the whole care team — organized and always in sync, so you are not retelling the same story to every new specialist. With Ellie, your AI care assistant, on top of it. Free to start.