A Case of Cochlear Implantation in a Deaf Patient With Eosinophilic Otitis Media in Whom Post-implantation Hearing Threshold Improved After Introduction of Dupilumab.

Eosinophilic otitis media (EOM) is a rare, intractable, and chronic form of otitis media. The associated hearing loss often progresses to deafness, necessitating cochlear implantation (CI). EOM is associated with type 2 inflammatory conditions such as asthma and chronic rhinosinusitis with nasal polyps (CRSwNP). Dupilumab, a monoclonal antibody targeting the IL4Rα subunit, has shown efficacy in mitigating type 2 inflammatory diseases, including asthma and CRSwNP. Recent studies also suggest its effectiveness in treating EOM. We report a unique case of CI for EOM, in which the post-implant hearing threshold improved after the introduction of dupilumab. The patient was a 63-year-old man with a history of asthma and multiple nasal polypectomies. Eosinophils were detected in otorrhea samples from both ears, leading to an EOM diagnosis four years prior. Despite local corticosteroid therapy, his hearing gradually deteriorated. One month ago, he experienced sudden bilateral deafness and was referred to our hospital. The right tympanic membrane had a pinhole perforation but no otorrhea. CT showed a small amount of soft tissue density in the right middle ear, while the left side displayed cochlear osteolysis with soft tissue density. A right CI and myringoplasty were performed one and a half months after his visit. The cochleostomy revealed no perilymph leakage, confirming that the scala tympani was filled with granulation tissue. The electrode was inserted successfully despite the granulation, and all electrodes were placed correctly. Six months after CI, his hearing threshold with the cochlear implant remained poor at 67.5 dB. However, upon starting dupilumab therapy seven months postoperatively, his hearing threshold with the cochlear implant rapidly improved to 31.3 dB. Intraoperative findings suggested that the scala tympani was filled with granulation tissue, indicating significant cochlear inflammation due to EOM. The subsequent hearing improvement after introducing dupilumab may be attributed to the reduction or disappearance of granulation in the cochlea, allowing for effective electrical stimulation from the electrodes to the spiral ganglion. This case suggests the potential for improved postoperative hearing outcomes in CI for EOM when inflammation is effectively controlled with dupilumab.