18th February 2025

Eosinophilic granulomatosis with polyangiitis

Eosinophilic granulomatosis with polyangiitis (EGPA) (previously Churg-Strauss syndrome) is an ANCA-positive, small- and medium-sized vasculitis characterised by chronic rhinosinusitis, asthma and eosinophilia. The most commonly involved organ is the lung. 

EGPA is typically associated with p-ANCA (versus c-ANCA in GPA), although the antibodies are not found in all patients. It is rare to find an isolated positive c-ANCA in EGPA and this would put the diagnosis of EGPA in serious doubt. Leucocytosis with eosinophilia is also a feature, as are raised CRP and ESR. Similarly to GPA, renal impairment can also be seen in EGPA.

Clinical features of EGPA

The clinical features of EGPA typically develop in three phases:

1. Prodromal phase: atopy, asthma and allergic rhinitis, sinusitis, nasal polyps
2. Eosinophilic phase: eosinophilic organ infiltration (e.g. in lung, heart, GI system) 
3. Vasculitic phase: purpura, peripheral neuropathy and constitutional symptoms

Asthma is the cardinal feature of EGPA. It should be suspected in patients with poorly controlled asthma on moderate doses of inhaled corticosteroids. EGPA-associated asthma often requires long-term courses of systemic glucocorticoids. Commonly, asthma exacerbations increase during the vasculitic phase but the initial asthmatic presentation may predate the vasculitic phase by up to 10 years. Haemoptysis is unusual, unlike in GPA and MPA. 

Other respiratory manifestations include:

• ENT involvement in 70-85% – otitis media, allergic rhinitis, nasal obstruction, sinusitis, nasal polyps
• Chronic rhinosinusitis can lead to chronic serous otitis media and sensorineural hearing loss
• Imaging findings of bilateral peripheral/random consolidation or ground-glass changes and eosinophilic pleural effusions

Investigation and management of EGPA

Investigation and treatment are similar to other ANCA-associated vasculitides, such as GPA and MPA.

Induction treatment is with cyclophosphamide and IV methylprednisolone, especially if there are organ- or life-threatening features. Rituximab can be a substitute for cyclophosphamide as per clinician preference.