Eosinophilic granulomatosis with polyangiitis (EGPA), until recently called Churg-Strauss syndrome is a systemic necrotizing vasculitis with multiple organ involvement, most commonly manifested by asthma, eosinophilia and necrotizing extravasal granulomas. Anti-neutrophil cytoplasmic autoantibodies (ANCA) are found in some of the patients. EGPA is one of the rarest forms of primary systemic vasculitis.Since the first description of the disease in 1951, its classification has undergone many changes aimed at refining the diagnostic process and timely treatment. In order to be diagnosed precisely, patients must meet certain criteria. The lack of a unified approach in the application of these criteria, as well as the overlap of clinical symptoms with other primary systemic vasculitides, make it difficult to study EGPA epidemiology.This publication aims to analyze epidemiological data on EGPA and to provide an assessment of the incidence and prevalence of this disease in Bulgaria. Read the whole article here.