Eosinophilic Granulomatosis with Polyangiitis: Experiences in Korean Patients

Eosinophilic granulomatosis with polyangiitis (EGPA) is one form of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. Identical to what has been called Churg-Strauss syndrome, EGPA exhibits both allergic and vasculitis features. EGPA was first described as a syndrome consisting of asthma, fever, eosinophilia, and organ involvement including heart failure, neuropathy, and kidney damage, by Churg and Strauss in 1951. On the basis of the 2012 Chapel Hill Consensus Conferences Nomenclature of Vasculitis, EGPA comprises three typical allergic components, including asthma, peripheral eosinophilia, and eosinophil-rich granuloma of the respiratory tracts. EGPA has three clinical and histological stages. The first is an allergic stage composed of asthma and sinusitis, and the second is an eosinophilic stage characterised by peripheral hypereosinophilia and intra-organ infiltration of eosinophils. The last is a vasculitic stage, including necrotising inflammation of small vessels and end-organ damage. In this review, we describe the classification criteria for EGPA and recommendations for the evaluation and management of EGPA with conventional and newly suggested drugs for EGPA. Also, we discuss a variety of clinical aspects such as predictive values for prognosis and associations with other Th2-mediated diseases and hepatitis B virus.