Eosinophilic Granulomatosis with Polyangiitis

Eosinophilic granulomatosis with polyangiitis (previously called Churg-Strauss syndrome) is an ANCA-associated vasculitis (along with granulomatosis with polyangiitis and microscopic polyangiitis), although the presence of ANCA occurs in < 50% of patients (usually anti-MPO).

It is characterized by peripheral eosinophilia, sinusitis with polyposis, asthma, lung infiltrates, vasculitic skin involvement, glomerulonephritis, and vasculitic neuropathy.

Myocarditis can lead to arrhythmias and heart failure if untreated.

Eosinophilic granulomatosis with polyangiitis should be considered in patients with an unexplained peripheral eosinophilia and vasculitis.

Laboratory workup for unexplained eosinophilia should include ANCA testing, serum tryptase levels, peripheral flow cytometry for PDGF receptor abnormalities (which can be seen in eosinophilic leukemia) and testing for helminthic infections.

Eosinophilic infiltrates on tissue samples strongly suggest the diagnosis of eosinophilic granulomatosis with polyangiitis, especially if accompanied by vasculitis (purpura, glomerulonephritis, vasculitic ulcers, mononeuritis multiplex).

Corticosteroids remain first-line treatment with azathioprine and methotrexate demonstrating efficacy for mild to moderate disease.

Mepolizumab, an IL-5 inhibitor, is FDA-approved for the treatment of eosinophilic granulomatosis with polyangiitis, although it has not been studied for severe life- or organ-threatening vasculitic disease manifestations (which generally require cyclophosphamide).