INTRODUCTION: Eosinophilic granulomatosis with polyangiitis (EGPA) was formerly known as Churg-Strauss syndrome. The condition is characterized by disseminated necrotizing vasculitis with extravascular granulomas associated with hypereosinophilia. The vasculitides affect small vessels and are associated with antineutrophil cytoplasmic antibodies (ANCAs) detectable in the blood. Distinguishing between type 2-mediated chronic airway inflammation such as chronic rhinosinusitis with nasal polyps (CRSwNP) without vasculitis can be clinically challenging and should be considered.

MATERIALS AND METHODS: Immunological background, diagnosis, and therapy of EGPA were identified through literature searches in Medline, PubMed, as well as national and international studies (ClinicalTrials.gov) and the Cochrane Library. Human studies published up to and including 10/2023 on the topic were considered.

RESULTS: In cases of deteriorating general health with previously known eosinophilic inflammation of the upper and lower airways, EGPA and its interdisciplinary investigation should be considered. Various types of eosinophilic inflammation and syndromes must be considered differentially.

CONCLUSION: Characterization of mucosal airway inflammation through biomarker determination is meaningful and occasionally makes the difference for targeted therapy.