What are the three clinical phases of Eosinophilic Granulomatosis with Polyangiitis?
These phases may appear simultaneously and do not have to follow one another in the order presented here.
1. Prodromal phase: this phase averages 28 months but may persist for years (2–7 years). It consists of allergic manifestations of rhinitis, polyposis, and most commonly asthma (80%–90%). Recurrent fevers occur in 50% of patients during this stage. Asthma frequently worsens prior to entering the second phase.
2. Peripheral blood and tissue eosinophilia develop, frequently causing a picture resembling Löffler’s syndrome (shifting pulmonary infiltrates and eosinophilia), chronic eosinophilic pneumonia, or eosinophilic gastroenteritis. Myocarditis can develop. Fevers are common during this phase. This second phase may remit or recur over years before the third phase.
3. Life-threatening systemic vasculitis. The onset of this phase occurs an average of 3 years after the onset of prodromal phase. The asthma can abruptly abate as the patient moves into this phase. Patients can develop myocarditis, valvular insufficiency, neurologic symptoms (most commonly a vasculitic peripheral neuropathy), eosinophilic gastroenteritis, purpura, and testicular pain.
