Eosinophilic granulomatosis with polyangiitis
Eosinophilic granulomatosis with polyangiitis (EGPA) is the rarest antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, defined by a three-phase course of late-onset asthma and rhinosinusitis, then peripheral and tissue eosinophilia, then small- and medium-vessel vasculitis with mononeuritis multiplex. ANCA is positive in only 40 to 60 percent of patients, cardiac involvement drives most mortality, and treatment is glucocorticoids alone for non-organ-threatening disease, glucocorticoids plus cyclophosphamide or rituximab for organ-threatening disease, and mepolizumab as steroid-sparing therapy.
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What this article covers
- Overview
Definition: eosinophilic granulomatosis with polyangiitis (EGPA), formerly called Churg-Strauss syndrome, is a rare small- and medium-vessel necrotizing vasculitis marked by eosinophil-rich…
- Epidemiology
The rarest ANCA-associated vasculitis: annual incidence is 0.11 to 2.66 per million, far below the 7 to 12 per million of GPA.
- Risk factors
Preexisting late-onset asthma: the dominant risk marker, typically severe and glucocorticoid-dependent, preceding the vasculitic phase by months to years.
- Pathophysiology
Eosinophil-driven tissue injury: eosinophil infiltration, activation, and degranulation participate in every phase of disease, producing tissue eosinophilia in the lungs and gastrointestinal tract before overt vasculitis develops.
- Clinical features
Phase 1, prodromal allergic phase: late-onset, often severe and glucocorticoid-dependent asthma with allergic rhinitis and nasal polyposis; this phase can persist for years before progression.
- Differential diagnosis
Granulomatosis with polyangiitis: shares upper airway, pulmonary, and renal disease, but more than 95 percent are ANCA positive (overwhelmingly anti-proteinase 3), renal involvement is far more…
- Diagnosis
First, confirm what establishes the diagnosis: EGPA is diagnosed from the three-phase clinical pattern plus marked eosinophilia, confirmed by biopsy showing fibrinoid necrosis and eosinophilic…
- Management
First, for non-organ-threatening (mild) disease without kidney, gastrointestinal, cardiac, or neurologic involvement: glucocorticoids alone are usually sufficient.
- Complications
Permanent neuropathy: mononeuritis multiplex, present in 70 percent of patients in the vasculitic phase, can become permanent if treatment is delayed.
- Prognosis
Best survival among the ANCA-associated vasculitides: 5-year survival is 97 percent, exceeding that of GPA and MPA.
- Prevention
No primary prevention exists: the cause of EGPA is unknown, so prevention centers on early recognition in severe, glucocorticoid-dependent asthma and on monitoring therapy.
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Related articles
- Granulomatosis with polyangiitis
Granulomatosis with polyangiitis (GPA) is an antineutrophil cytoplasmic antibody (ANCA)-associated necrotizing granulomatous vasculitis of the upper airway, lower airway, and kidney, most often with cytoplasmic ANCA (c-ANCA) targeting proteinase 3 (PR3). Diagnosis rests on the clinical triad, ANCA serology, and tissue biopsy showing pauci-immune vasculitis, and treatment begins with high-dose glucocorticoids plus rituximab or cyclophosphamide for organ-threatening disease, followed by rituximab or azathioprine maintenance.
- Microscopic polyangiitis
Microscopic polyangiitis (MPA) is a pauci-immune small-vessel vasculitis, almost always with perinuclear antineutrophil cytoplasmic antibody (p-ANCA) targeting myeloperoxidase (MPO), that causes rapidly progressive crescentic glomerulonephritis and pulmonary alveolar hemorrhage without the granulomas, eosinophilia, or upper-airway disease of its ANCA-associated siblings. Diagnosis combines urine microscopy, ANCA serology, and biopsy, and treatment is glucocorticoids plus rituximab or cyclophosphamide induction followed by rituximab or azathioprine maintenance.
- Vasculitis: an overview
Vasculitis is inflammation and necrosis of blood vessel walls, classified by the Chapel Hill scheme into large, medium, small (ANCA-associated versus immune-complex), and variable-vessel disease, each with a vessel-size-predicted clinical syndrome. Diagnosis requires excluding mimics such as infective endocarditis and cholesterol embolization before confirming with serology and biopsy, and treatment is glucocorticoid induction plus cyclophosphamide or rituximab for organ-threatening disease.
- Asthma
Asthma is a chronic inflammatory airway disorder causing episodic, reversible airflow obstruction confirmed by spirometry or bronchial challenge testing. Management is a stepwise ladder led by inhaled glucocorticoids plus as-needed SABA or ICS-formoterol, escalating to biologics for severe type 2-high disease, with an oral glucocorticoid burst and frequent SABA for exacerbations.
- Chronic rhinosinusitis
Chronic rhinosinusitis is inflammation of the paranasal sinuses lasting 12 weeks or longer, confirmed by nasal endoscopy or CT, and treated first with intranasal corticosteroids and saline irrigation before escalation to antibiotics, oral steroids, biologics, or surgery.