Synopsis
Recognise eosinophilic granulomatosis with polyangiitis across asthma, eosinophilic tissue disease and vasculitis, exclude parasitic, drug and clonal eosinophilia, detect cardiac and neurological emergencies, and match induction and biologic treatment to organ severity.
- Suspect EGPA when adult-onset asthma and chronic rhinosinusitis accompany eosinophilia, migratory lung infiltrates, purpura, neuropathy, cardiac, renal or gastrointestinal disease.
- Check the absolute eosinophil count before high-dose steroid when safe, because glucocorticoid can normalise it rapidly and obscure phenotype.
- MPO-ANCA supports a vasculitic subset but most patients can be ANCA-negative; never use a negative test to dismiss eosinophilic myocarditis or neuropathy.
Key red flags
Chest pain, syncope, arrhythmia, troponin rise, ventricular dysfunction or unexplained dyspnoea may indicate eosinophilic myocarditis even without striking CRP.
Acute painful asymmetric sensory loss and foot or wrist drop is a classic organ-threatening vasculitic feature.
Investigation priorities
Confirm eosinophilia before steroid and identify clonal or reactive haematological clues.
Management branches
Asthma or sinus disease accompanies eosinophilia and systemic organ features.
- Record the pre-steroid eosinophil count, travel, medicines, atopy, asthma trajectory and skin, nerve, heart, lung, renal and gut findings.
- Send ANCA, urine, renal, cardiac and lung tests and a phenotype-directed parasite, fungal and clonal-eosinophilia screen.
Key medicines
PrednisoloneFor active systemic EGPA use 0.5–1 mg/kg orally once daily, with intravenous methylprednisolone 500 mg–1 g daily for three days in critical organ disease, followed by a planned taper.
BenralizumabFor adult relapsing or refractory EGPA use 30 mg subcutaneously once every four weeks as add-on treatment under NICE TA1096 and specialist supervision.