(853) Immunosuppressive Therapy for Sudden Sensorineural Hearing Loss as Initial Immune-Mediated Inner Ear Disease Presentation

Introduction: Sudden sensorineural hearing loss (SSNHL) poses a major therapeutic challenge when standard corticosteroid therapy fails, often suggesting an underrecognized immune-mediated mechanism. Identifying the clinical signature of Immune-Mediated Inner Ear Disease (IMED) is critical to move from empirical care to targeted immunosuppression. This study assessed the auditory salvage potential of immunosuppressive regimens in patients whose SSNHL was the initial manifestation of IMED.

Methods: In this prospective cohort (January 2023–March 2025) at a tertiary clinic, 111 SSNHL patients were evaluated; 11 (9.9%, 18 ears) met IMED criteria. Workup included clinical and audiologic assessment, autoimmunity markers, and inner-ear MRI when indicated. All received systemic corticosteroids initially, followed by steroid-sparing therapy (methotrexate, azathioprine, cyclophosphamide, and/or rituximab). Outcomes were audiometric change at follow-up (improvement, stability, or worsening); preliminary analyses were descriptive.

Results: Mean age was 46 ± 12.8 years; 63.6% had bilateral disease and vestibular symptoms, and 54.5% had secondary IMED. Regimens included methotrexate (36.4%), cyclophosphamide (45.5%), azathioprine (9.1%), and rituximab (36.4%). Across 18 ears, outcomes were improvement in 44.4%, stability in 33.3%, and worsening in 22.2%. Importantly, hearing improvement or stabilization was observed after initiation of immunosuppressants/immunobiologics, including delayed responses weeks to months after the initial event and after corticosteroid failure. Earlier intervention was associated with higher recovery (70% vs 30%).

Conclusions: IMED should be considered in SSNHL refractory to initial therapy. Immunosuppressive/immunobiologic treatment can achieve meaningful hearing improvement or stability beyond the acute phase, supporting an extended therapeutic window and the need for early multidisciplinary otology–rheumatology management.