EGPA and IgG4-RD do share some features, such as history of allergic disease, elevated serum Immunoglobulin E (IgE), and elevated serum IgG4, but the pathogenesis of each disease differs substantially [9]. The patient did not meet IgG4-RD classification criteria [10] given the lack of clinical criteria, whereas he did meet EGPA classification criteria [11] based on small vessel eosinophilic vasculitis on sinus biopsy, asthma, nasal polyposis, and peripheral eosinophilia. The gene discussed is IGHE; the disease is eosinophilic granulomatosis with polyangiitis.