Eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome)

The severity of the disease and the treatment required will dictate the follow-up needed. Patients treated with cyclophosphamide require frequent complete blood count monitoring to ensure assessment for leukopenia. This should be weekly, at least initially. They should have initial laboratory and radiographic studies repeated up to several times a year, at least initially. There is some evidence that the recurrence of antineutrophil cytoplasmic antibody may coincide with and often predate the onset of vasculitic flare, suggesting a potential role in follow-up assessment. Before starting azathioprine, where available, patients should have their thiopurine methyltransferase enzyme levels/genotype assessed, to ensure that they have sufficient enzyme levels to metabolize the drug.