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Health condition

Churg-Strauss syndrome (EGPA), where asthma, eosinophils and vasculitis meet.

A rare ANCA-associated vasculitis that hides inside adult-onset asthma. Modern treatment, from rituximab to anti-IL-5 biologics, has changed what life with EGPA looks like.

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Why trust this guide

  • 01

    Editorial team

    Written by our editorial team from the UK sources listed on each page.

  • 02

    Sourced from guidance

    Checked against EULAR 2022, BSR 2014, ACR/EULAR 2022 classification criteria and peer-reviewed vasculitis literature.

  • 03

    Current for 2026

    Reflects modern management including mepolizumab, benralizumab (MANDARA 2024) and rituximab-based induction.

Key facts

EGPA at a glance.

The essentials in plain English: what EGPA is, why the asthma link matters, and how UK teams treat it today.

  • What it is

    Eosinophilic granulomatosis with polyangiitis (EGPA), the current name for Churg-Strauss syndrome. A rare ANCA-associated small to medium vessel vasculitis with tissue eosinophilia, granulomas and necrotising vasculitis.

  • How rare

    Around 2 to 5 cases per 100,000 people. It usually appears in mid-adulthood, often in someone with long-standing severe asthma.

  • Two subtypes

    ANCA-positive (around 40 percent, MPO-ANCA) with more vasculitic features, renal disease and peripheral neuropathy. ANCA-negative (around 60 percent) with more cardiac and eosinophilic tissue disease.

  • The asthma link

    Around 95 percent of patients have adult-onset asthma, often severe and poorly controlled, with allergic rhinitis and nasal polyps.

  • Classic three phases

    Prodromal (asthma and rhinitis, sometimes for years), eosinophilic infiltrative (tissue infiltration of lung, gut, heart), then vasculitic (small vessel vasculitis and organ damage).

  • Modern treatment

    Steroids and rituximab or cyclophosphamide for induction, then anti-IL-5 biologics such as mepolizumab (MIRRA) and benralizumab (MANDARA) to spare steroids and reduce relapses.

Why this guide matters

A rare disease that rewards early recognition.

EGPA often lives inside "difficult asthma" for years before it declares itself. Naming it earlier changes the trajectory.

  • Adult-onset asthma is the clue

    Around 95 percent of patients have severe adult-onset asthma with nasal polyps. Any escalating asthma with high eosinophils deserves a serious look.

  • Cardiac disease drives mortality

    Endomyocarditis and myocardial fibrosis are the leading cause of death, which is why cardiac MRI and cardiology are now part of routine EGPA care.

  • Biologics have rewritten the plan

    Mepolizumab (MIRRA) and benralizumab (MANDARA) let many patients come off high-dose steroid while staying in remission.

How the diagnosis is made

From severe asthma to a named vasculitis.

The steps a UK respiratory, rheumatology or specialist vasculitis team will typically follow, in order, so you know what to expect and why.

  1. 01

    Suspecting

    Structured history and exam

    Long-standing adult-onset asthma, rhinosinusitis, nasal polyps, numb or weak limbs, purpuric rash, breathlessness, chest pain or weight loss all raise suspicion.

  2. 02

    Suspecting

    Bloods and eosinophil count

    FBC often shows marked eosinophilia over 1500 per microlitre or more than 10 percent of white cells. CRP, ESR and total IgE are usually raised.

  3. 03

    Suspecting

    Organ screen

    U&Es and creatinine for renal involvement, LFTs, and troponin plus BNP to screen for cardiac disease, which drives most of the mortality.

  4. 04

    Confirming

    ANCA testing

    MPO-ANCA is positive in around 40 percent and tracks with vasculitic, renal and neurological features. A negative ANCA does not rule EGPA out.

  5. 05

    Confirming

    Urinalysis and microscopy

    Dipstick for blood and protein, with microscopy looking for red cell casts that suggest glomerulonephritis.

  6. 06

    Confirming

    Targeted biopsy

    Skin, nerve, muscle, kidney, lung or gut biopsy looking for eosinophil-rich necrotising granulomatous inflammation and small vessel vasculitis.

  7. 07

    Confirming

    Imaging

    Chest X-ray and HRCT for peripheral eosinophilic infiltrates, nodules and effusions. CT of the sinuses for polyp burden. Cardiac MRI for fibrosis and late gadolinium enhancement, since subclinical myocarditis is common.

  8. 08

    Classifying

    Lung, nerve and heart tests

    Lung function and peak flow, nerve conduction studies and EMG for mononeuritis multiplex, echocardiogram and cardiology review. BAL may show striking eosinophilia.

  9. 09

    Classifying

    Classification and specialist MDT

    ACR/EULAR 2022 classification criteria confirm EGPA. Referral to a UK specialist vasculitis service (Cambridge, Imperial Hammersmith, Chapel Allerton, Manchester, Sheffield, Belfast, Edinburgh or Cardiff) shapes long-term care.

Typical timeline: from first serious suspicion to a specialist MDT plan in weeks.

Symptoms

What EGPA actually looks like.

Three overlapping phases: prodromal asthma and rhinitis, then eosinophilic infiltration, then true small vessel vasculitis. Every patient looks slightly different.

  • Late-onset severe asthma

    Adult-onset asthma that is difficult to control despite maximal inhaled therapy, often with recurrent exacerbations.

  • Rhinosinusitis and nasal polyps

    Chronic nasal congestion, loss of smell, sinus pain and recurrent nasal polyps, often needing repeated ENT surgery.

  • Peripheral neuropathy

    Mononeuritis multiplex is classic. Sudden foot drop or wrist drop, painful patchy numbness or weakness in more than one nerve distribution.

  • Skin changes

    Palpable purpura, tender subcutaneous nodules, livedo reticularis or ulcers, usually on the lower legs.

  • Cardiac involvement

    Endomyocarditis, myocardial fibrosis and heart failure. Cardiac disease is the leading cause of mortality in EGPA.

  • Gastrointestinal disease

    Eosinophilic gastroenteritis, mesenteric ischaemia, bleeding or, rarely, bowel perforation causing severe abdominal pain.

  • Renal and pulmonary disease

    Glomerulonephritis (usually milder than in GPA or MPA), eosinophilic pneumonia, migratory infiltrates and, uncommonly, alveolar haemorrhage.

  • Red flag - organ-threatening flare

    New foot drop, new confusion, chest pain, haemoptysis, oliguria or severe abdominal pain need same-day specialist review.

Treatment

How EGPA is treated in the UK.

Steroids and immunosuppression to induce remission, biologics to spare steroid and prevent relapse, and full attention to airways, sinuses and the heart.

  • High-dose prednisolone

    Oral prednisolone around 1 mg/kg daily is the cornerstone of induction, with IV methylprednisolone pulses reserved for severe organ-threatening disease.

  • Cyclophosphamide

    IV or oral cyclophosphamide is used for severe organ-threatening disease including cardiac, neurological, renal, gut or alveolar haemorrhage involvement.

  • Rituximab

    An anti-CD20 biologic used as an alternative to cyclophosphamide, and increasingly first line in ANCA-positive or relapsing disease, informed by the PEXIVAS and REVEAL trials.

  • Maintenance immunosuppression

    Azathioprine, methotrexate, mycophenolate or rituximab, alongside a slow prednisolone taper, to keep the vasculitis in remission.

  • Mepolizumab (anti-IL-5)

    Nucala 300 mg subcutaneously monthly. The MIRRA trial (2017) made it the first biologic licensed specifically for EGPA. Cuts relapses and spares steroid.

  • Benralizumab (anti-IL-5R)

    Fasenra 30 mg subcutaneously every 4 weeks then 8-weekly. The MANDARA trial (2024) showed non-inferiority to mepolizumab in EGPA, with growing NHS use.

  • Airway and sinus care

    Optimised inhaled corticosteroid and LABA/LAMA regimens, severe asthma clinic input and ENT review for nasal polyps and chronic rhinosinusitis.

  • Cardiac and supportive care

    Heart failure therapy, cardiology follow-up, PJP prophylaxis with co-trimoxazole, bone protection, vaccinations, a PPI and regular BVAS-based relapse monitoring.

Biologic therapy is delivered through a severe asthma and vasculitis clinic. See our asthma biologics clinic and biologics infusion clinic for how these are set up in practice.

What this guide is based on

The sources behind every claim on this page.

UK and international guidance and the key randomised trials that shape modern EGPA care, current at the time of last review.

Key references

Guidelines and trials we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP, respiratory physician or vasculitis specialist knows your history and can tell you which parts apply to you. If in doubt, get seen.

  • EULAR 2022 recommendations for the management of ANCA-associated vasculitis.

  • BSR and BHPR 2014 guideline for the management of adults with ANCA-associated vasculitis.

  • ACR/EULAR 2022 classification criteria for eosinophilic granulomatosis with polyangiitis.

  • Wechsler et al. MIRRA trial: mepolizumab in EGPA. N Engl J Med, 2017.

  • Wechsler et al. MANDARA trial: benralizumab versus mepolizumab in EGPA. N Engl J Med, 2024.

  • PEXIVAS and REVEAL trial data on plasma exchange, glucocorticoid regimens and rituximab in ANCA-associated vasculitis.

  • Vasculitis UK. Patient information on EGPA (Churg-Strauss syndrome).

Red flags

When EGPA needs urgent attention.

EGPA can move quickly. These situations need same-day or emergency review with your vasculitis team or A&E.

  • New mononeuritis multiplex

    Sudden foot drop, wrist drop or patchy limb weakness with pain needs urgent neurology and vasculitis review to prevent permanent damage.

  • Chest pain or breathlessness

    Cardiac EGPA is the biggest driver of mortality. New chest pain, breathlessness at rest or arrhythmia needs same-day cardiology input.

  • Alveolar haemorrhage

    Haemoptysis with breathlessness and falling haemoglobin is a medical emergency and warrants immediate hospital admission.

  • Rapidly rising creatinine

    Falling urine output, new leg swelling or a rising creatinine with blood and protein on dipstick suggests rapidly progressive glomerulonephritis.

  • Severe abdominal pain

    Mesenteric ischaemia, gut perforation and eosinophilic gastroenteritis can present as severe abdominal pain, vomiting or per-rectum bleeding.

  • Uncontrolled asthma flare

    A sudden loss of asthma control, especially with rising eosinophils or new systemic symptoms, can herald an EGPA relapse.

  • New neurological symptoms

    Confusion, stroke-like symptoms, cranial nerve palsies or seizures need urgent imaging and specialist review.

  • Infection on immunosuppression

    Fever, cough or shortness of breath on rituximab, cyclophosphamide or high-dose steroid needs same-day medical assessment.

  • Steroid withdrawal symptoms

    Fatigue, dizziness, nausea and abdominal pain during a rapid taper can reflect adrenal insufficiency and needs urgent review.

Living with it

A rare disease, with a clear team behind you.

Four things that make the biggest difference over years: the right specialist team, careful monitoring, protecting bones and lungs from treatment side effects, and peer support.

A quiet reminder

Remission is real, and increasingly durable.

With modern induction, maintenance and biologic care, most people with EGPA can expect long periods of stable disease and, for many, a life off high-dose steroid.

  1. 01 Team

    Stay under a specialist vasculitis MDT

    Rheumatology, respiratory, cardiology, neurology, immunology and ENT working together give the best long-term outcomes.

  2. 02 Monitor

    Track flares with BVAS and eosinophils

    Regular clinical scoring, eosinophil counts, ANCA and organ tests catch relapses early, before organs are damaged.

  3. 03 Protect

    Bones, infections and vaccines

    Bone protection, PJP prophylaxis, annual flu, COVID and pneumococcal vaccines matter as much as the vasculitis drugs.

  4. 04 Support

    You are not alone with a rare disease

    Vasculitis UK and specialist nurse teams offer peer support, benefits advice and help navigating the NHS specialist network.

Frequently asked

Everything we get asked about EGPA.

Quick answers on diagnosis, ANCA subtypes, biologics and specialist UK care.

  • What is Churg-Strauss syndrome now called?

    Since 2012 it has been renamed eosinophilic granulomatosis with polyangiitis, or EGPA. It is a rare ANCA-associated small to medium vessel vasculitis marked by adult-onset asthma, tissue eosinophilia, granulomas and necrotising vasculitis affecting the lungs, skin, nerves, heart, gut and kidneys.

  • How is EGPA diagnosed?

    Diagnosis brings together a compatible clinical picture (late-onset asthma, rhinosinusitis, nasal polyps, neuropathy and other organ features), blood eosinophilia (typically over 1500 per microlitre), MPO-ANCA testing, targeted biopsy, imaging including HRCT and cardiac MRI, and nerve conduction studies. The ACR/EULAR 2022 classification criteria formalise the picture.

  • What is the difference between ANCA-positive and ANCA-negative EGPA?

    Around 40 percent of patients are MPO-ANCA positive, with more vasculitic features, peripheral neuropathy and glomerulonephritis. Around 60 percent are ANCA-negative and tend to have more eosinophilic tissue disease, especially cardiac and pulmonary involvement. The distinction increasingly guides treatment choice.

  • Why are mepolizumab and benralizumab important in EGPA?

    Both are anti-IL-5 pathway biologics that target the eosinophilic engine of the disease. Mepolizumab (MIRRA, 2017) was the first biologic licensed specifically for EGPA and cuts relapses and steroid use. Benralizumab was shown to be non-inferior to mepolizumab in the MANDARA trial (2024) and is expanding into NHS practice.

  • Which organ involvement is most serious in EGPA?

    Cardiac disease. Endomyocarditis, myocardial fibrosis and heart failure are the leading cause of death in EGPA and can be subclinical, which is why cardiac MRI and specialist cardiology input are routine in modern care.

  • Where in the UK is EGPA usually looked after?

    EGPA is managed at specialist vasculitis services including Addenbrooke’s in Cambridge, Hammersmith at Imperial, Chapel Allerton in Leeds, Manchester, Sheffield, Belfast, Edinburgh and Cardiff. Local rheumatology, respiratory and cardiology teams share care with these centres, supported by Vasculitis UK.

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