What's eosinophilic granulomatosis with polyangiitis?
Eosinophilic granulomatosis with polyangiitis (EGPA), formerly Churg-Strauss syndrome, is a small- and medium-vessel vasculitis defined by asthma, marked eosinophilia in blood and tissue, and eosinophil-rich granulomatous inflammation. Unlike the other ANCA-associated vasculitides, ANCA is detectable in only about a third of patients, so its absence does not rule the diagnosis out.
| Also indexed as | ORPHA:183, MONDO:0015943 |
|---|---|
| Features mapped | 10 |
| Treatments mapped | 4 |
| Published sources | 14 |
| Last reviewed | 2026-08-04 |
Signs and symptoms
Multiple mononeuropathy
The vasculitis can damage individual nerves in a patchy, asymmetric pattern called mononeuritis multiplex, often felt as numbness, weakness, or foot drop. It is one of the more common ways the systemic disease first declares itself.
Peripheral neuropathy
Peripheral neuropathy, which is nerve damage causing numbness, weakness, or pain in the limbs, is a common feature of eosinophilic granulomatosis with polyangiitis.
Myocarditis
The heart can be affected when eosinophils infiltrate the heart muscle (eosinophilic myocarditis). Cardiac involvement is one of the most serious aspects of the disease and a leading driver of poor outcomes, so doctors look for it carefully.
Vasculitis
Eosinophilic granulomatosis with polyangiitis involves vasculitis, which is inflammation of the blood vessels, affecting small-to-medium-sized vessels along with eosinophil buildup in multiple organs.
Pulmonary infiltrates
The lungs are frequently involved, with patchy shadows (pulmonary infiltrates) on chest imaging that reflect eosinophil accumulation in lung tissue.
Increased total eosinophil count
A high eosinophil count in the blood (eosinophilia) is a central, near-defining feature. These allergy-related white blood cells build up and infiltrate tissues, driving much of the organ damage.
Anti-myeloperoxidase antibody positivity
When ANCA is present, it is usually the myeloperoxidase type (MPO-ANCA, or p-ANCA). Only about a third to 40% of people with the condition test ANCA-positive, so a negative test does not exclude it.
Asthma
Asthma is the most consistent feature, present in almost everyone with the condition, and is usually adult-onset. It often comes first, years before the vasculitis is recognized.
Sinusitis
Sinus inflammation is one of the early symptoms of eosinophilic granulomatosis with polyangiitis, often appearing along with nasal inflammation and asthma before the condition is recognized.
Nasal polyposis
Upper-airway allergy is common: chronic sinus inflammation (rhinosinusitis) and nasal polyps (soft growths in the nasal lining) often appear early.
How it is diagnosed
Eosinophilic granulomatosis with polyangiitis
Diagnosed using: tissue biopsy.
“Transbronchial biopsy (TBB) was performed in 93 patients, with 76 (81.7%) showing pathological support for EGPA, including eosinophilic infiltration in 72 patients (77.4%), vasculitis in 23 patients (24.7%), and granulomas in 7 patients…”
Treatment and management
What the research describes, not a recommendation. Treatment decisions belong with your clinician.
This covers treatments that appear in the published research mapped here. Investigational and experimental therapies are not included, so their absence is a boundary of this map, not a sign they do not exist.
corticosteroids
Corticosteroids (steroids such as prednisolone, often started at high dose) are the first-line treatment and quickly lower the eosinophil count and inflammation. Long-term control then aims to taper the steroid dose down.
Used to help with: Eosinophilic granulomatosis with polyangiitis.
“After receiving high-dose…”
mepolizumab
Mepolizumab is an antibody that blocks interleukin-5, the signal that drives eosinophils to grow and survive. It is approved specifically for this condition and helps achieve remission while reducing how much steroid a person needs.
Used to help with: Eosinophilic granulomatosis with polyangiitis.
“Mepolizumab (MPZ), an anti-interleukin-5 monoclonal antibody, has emerged as an effective treatment for patients with EGPA.”
cyclophosphamide
Cyclophosphamide, a strong immune-suppressing medicine, is used for severe, organ-threatening disease such as serious nerve, heart, or kidney involvement.
Used to help with: Eosinophilic granulomatosis with polyangiitis.
“…intravenous cyclophosphamide, with substantial neurological…”
rituximab
Rituximab, which depletes the B cells that make autoantibodies, is another option for inducing and maintaining remission, particularly in ANCA-positive or relapsing disease.
Used to help with: Eosinophilic granulomatosis with polyangiitis.
“Rituximab is now central to remission induction and…”
What changes how it shows up
The diagnosis is not the whole story. The factors and open questions below are described in the research mapped here as shaping whether, or how strongly, the condition shows up, or as points the field has not yet settled. They are not, on their own, its cause or its cure.
ANCA status
Only a minority of people with eosinophilic granulomatosis with polyangiitis test positive for ANCA (anti-neutrophil cytoplasmic antibodies); in one cohort about one in six were positive, so a negative result does not rule the condition out.
Described as modulating: Eosinophilic granulomatosis with polyangiitis.
“ANCA positivity was found in 18 patients…”
ANCA status and cardiac risk
Heart involvement in eosinophilic granulomatosis with polyangiitis is not reliably predicted by whether a person is ANCA-positive or ANCA-negative, so cardiac problems can develop regardless of antibody status.
Described as modulating: Eosinophilic granulomatosis with polyangiitis.
“Cardiac involvement may progress despite improvement in systemic manifestations and is not reliably predicted by antineutrophil cytoplasmic antibody…”
How to read the evidence labels
Where this comes from
This guide is built from 14 published source(s). Every claim above links back to one of them. Click any source ID to read the original on PubMed.
Take it further
Printed, source-linked documents built from this condition's graph — ready to bring to an appointment or attach to a coverage request. Every claim carries its published source, the same as this guide.