A Pediatric Case of Relapsing Eosinophilic Granulomatosis with Polyangiitis Successfully Treated with Mepolizumab.

We herein report the first pediatric case (a 13-year-old girl) of relapsing eosinophilic granulomatosis with polyangiitis (EGPA) successfully treated with mepolizumab (anti-interleukin-5). She was classified as having EGPA based on the presence of asthma, eosinophilia, pulmonary infiltrates, and extravascular eosinophil infiltration confirmed by a biopsy. She achieved remission after initial oral prednisolone (PSL) therapy, but EGPA relapsed during PSL tapering. Subsequent combined therapy with PSL and tacrolimus did not improve the recurrent disease. Intravenous methylprednisolone pulse therapy was started, followed by oral PSL. During PSL tapering, mepolizumab was added to the treatment, which resulted in sustained remission and successful PSL tapering.