Eosinophilic granulomatosis with polyangiitis (Churg–Strauss) !
A rare vasculitis of small vessels in people with asthma and high eosinophils that can damage nerves, heart, lungs, skin and kidneys.
Updated 2026-11-01
Structures involved
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Why it happens
- Granulomatous inflammation: caseating vs non-caseating, the causes to know
- White blood cells: types and functions
- Blood vessels: artery, vein and capillary layers
What it is
An ANCA-associated, necrotising small-vessel vasculitis with eosinophil-rich granulomatous inflammation. It typically develops in an adult with late-onset asthma and chronic rhinosinusitis with nasal polyps, followed by marked blood eosinophilia and then vasculitis affecting nerves, skin, heart, lungs, gut and kidneys.
Who gets it
The rarest of the ANCA-associated vasculitides, with a few cases per 100,000 people. It usually appears between 40 and 60 years and affects men and women about equally. Latin American data are scarce; in Colombia it is managed in referral rheumatology centres.
Causes
- Cause unknown; an autoimmune process with eosinophil and Th2 activation
- About 30–40% are positive for ANCA, mostly MPO-ANCA (p-ANCA)
- Genetic factors (HLA-DRB4) and environmental or allergic exposures are suspected
- Onset has occasionally followed reduction of corticosteroids in asthma or exposure to certain drugs
Risk factors
- Late-onset or difficult-to-control asthma
- Chronic rhinosinusitis with nasal polyps and allergic rhinitis
- Middle age
- History of atopy
Pathophysiology
Classically evolves in three overlapping phases: a prodromal allergic phase (asthma, rhinosinusitis), an eosinophilic phase (blood and tissue eosinophilia, pulmonary infiltrates, gastroenteritis) and a vasculitic phase. Eosinophils release toxic granule proteins that damage tissue, especially the heart; ANCA-positive patients more often have vasculitic features such as glomerulonephritis and neuropathy, whereas ANCA-negative patients more often have heart and lung disease.
Classification
- Prodromal (allergic) phase: asthma, allergic rhinitis, nasal polyps
- Eosinophilic phase: blood eosinophilia, pulmonary infiltrates, eosinophilic gastroenteritis
- Vasculitic phase: mononeuritis multiplex, purpura, glomerulonephritis
- ANCA-positive versus ANCA-negative phenotypes
Symptoms and signs
- Asthma that worsens or becomes harder to control in adulthood
- Nasal obstruction, polyps and chronic sinusitis
- Foot or wrist drop, numbness and pain from mononeuritis multiplex
- Palpable purpura and skin nodules
- Fever, weight loss, fatigue and muscle or joint pain
- Chest pain, breathlessness or palpitations from heart involvement; abdominal pain
Diagnosis
- Clinical
- Suspected in an adult with asthma, eosinophilia above 10% (or above 1,500 cells/µL) and features of vasculitis such as mononeuritis multiplex. Classification uses the 2022 ACR/EULAR criteria, which weight obstructive airway disease, nasal polyps, mononeuritis multiplex and eosinophilia.
- Tests
- Complete blood count with marked eosinophilia; raised IgE, ESR and CRP; ANCA (MPO by ELISA) positive in a minority; urinalysis and creatinine; troponin, ECG and NT-proBNP; stool tests and serology to exclude Strongyloides before steroids. Biopsy (skin, nerve, lung) shows eosinophil-rich necrotising vasculitis or granulomas; nerve conduction studies for neuropathy.
- Imaging
- Chest radiograph or CT showing migrating patchy infiltrates; sinus CT; echocardiography and cardiac MRI to detect myocarditis.
Differential diagnosis
- Granulomatosis with polyangiitis and microscopic polyangiitis
- Chronic eosinophilic pneumonia and hypereosinophilic syndrome
- Allergic bronchopulmonary aspergillosis
- Parasitic infection such as strongyloidiasis
- Drug reaction with eosinophilia
- Polyarteritis nodosa
Goal of treatment
Induce remission quickly to protect the heart, nerves and kidneys, then maintain remission with the least corticosteroid possible while keeping asthma controlled.
Treatment
- Acute
- Severe organ-threatening disease (heart, kidney, nerve, gut): high-dose systemic corticosteroids, often intravenous pulses, with cyclophosphamide or rituximab for induction.
- Medical
- Non-severe disease: systemic corticosteroids, adding anti-IL-5 therapy (mepolizumab, benralizumab) to control eosinophils and asthma and spare steroids.
- Medical
- Maintenance with azathioprine, methotrexate or anti-IL-5 therapy; inhaled therapy for asthma; treatment of Strongyloides before immunosuppression in endemic areas such as Colombia.
- Follow-up
- Monitoring of eosinophil count, ESR, kidney function, heart status and neuropathy; nursing care for falls with foot drop, infection prevention and steroid side effects (glucose, blood pressure, bone).
Complications
- Eosinophilic myocarditis, cardiomyopathy and heart failure
- Permanent peripheral neuropathy
- Glomerulonephritis and kidney failure
- Intestinal ischaemia or perforation
- Steroid dependence because of persistent asthma
Prognosis
With treatment most patients reach remission and five-year survival exceeds 90%, but relapses are common and many need long-term low-dose corticosteroids for asthma. Heart involvement is the main determinant of poor outcome.
Test yourself
Think of the answer, then tap the question to see it.
What triad suggests eosinophilic granulomatosis with polyangiitis?
Adult-onset asthma, marked peripheral eosinophilia and systemic vasculitis (for example mononeuritis multiplex).
Which ANCA pattern is most associated with EGPA, and how often is it positive?
p-ANCA (anti-MPO), positive in only about a third to 40% of patients.
What is the leading cause of death in EGPA?
Cardiac involvement (eosinophilic myocarditis or cardiomyopathy).
Which parasitic infection should be excluded or treated before high-dose steroids in a patient with eosinophilia from Colombia?
Strongyloidiasis, to avoid hyperinfection syndrome.
Related conditions
- Asthma
- Chronic rhinosinusitis and nasal polyps
- Eosinophilic pneumonias (including Löffler syndrome)
- Allergic bronchopulmonary aspergillosis (ABPA)
- Strongyloidiasis
- Granulomatosis with polyangiitis
- Microscopic polyangiitis
- Peripheral neuropathy (diabetic and other)
- Myocarditis
- Dilated cardiomyopathy
- Rapidly progressive glomerulonephritis (anti-GBM, ANCA)
Educational information, not medical advice. For any symptom, see a health professional.
Sources: Eosinophilic Granulomatosis with Polyangiitis, formerly Churg-Strauss Syndrome (EGPA) (Johns Hopkins Vasculitis Center, 2026); Vasculitis (MedlinePlus (U.S. National Library of Medicine), 2026).
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