Abstract / Summary
Dupilumab is effective for eosinophilic chronic rhinosinusitis (ECRS); however, eosinophilic granulomatosis with polyangiitis (EGPA) may become clinically apparent after treatment initiation.We retrospectively reviewed three patients with chronic rhinosinusitis with nasal polyps who developed systemic manifestations leading to a diagnosis of EGPA shortly after dupilumab initiation.All three patients had bronchial asthma and peripheral eosinophilia before treatment.EGPA developed within two weeks to two months after dupilumab initiation, with manifestations including fever, arthralgia, peripheral neuropathy, weight loss, and hypertrophic pachymeningitis.Two patients achieved remission with systemic corticosteroids and mepolizumab, whereas one patient with pre-existing myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) positivity had a fatal outcome despite intensive immunosuppressive therapy.Their pretreatment courses suggested that systemic eosinophilic disease may already have been evolving before biologic therapy, particularly in the patient with pre-existing MPO-ANCA positivity.Notably, the timing at which EGPA criteria were fulfilled differed between Japan's Ministry of Health, Labour and Welfare (MHLW) diagnostic criteria and the European Alliance of Associations for Rheumatology/American College of Rheumatology (EULAR/ACR) classification criteria in these patients, highlighting that reliance on a single set of criteria may delay recognition of evolving EGPA.These cases emphasize the importance of evaluating unexplained marked eosinophilia, ANCA positivity, and systemic symptoms before initiating dupilumab and of distinguishing transient treatment-associated eosinophilia from emerging systemic vasculitis during follow-up.