Optimal Timing of Intratympanic Corticosteroid Therapy for Idiopathic Sudden Sensorineural Hearing Loss: A...

Idiopathic sudden sensorineural hearing loss (ISSNHL) is an otologic emergency. While systemic corticosteroids are first-line therapy, intratympanic corticosteroid (ITC) injection has emerged as an important modality. The optimal timing of ITC-as primary therapy, combined initial treatment, or salvage therapy-remains controversial. To critically synthesize current evidence regarding ITC efficacy at different treatment timings and provide evidence-based clinical recommendations. A structured search of PubMed, Embase, and the Cochrane Library was conducted from database inception to December 2025 using terms sudden sensorineural hearing loss, ISSNHL, sudden deafness, intratympanic injection, ITC, intratympanic dexamethasone, and intratympanic methylprednisolone. The search identified 321 records, and additional articles were found in the reference lists of key reviews, meta-analyses, and guidelines. Studies were selected using predefined criteria, prioritizing randomized controlled trials, systematic reviews, meta-analyses, clinical practice guidelines, and relevant observational studies in adults with ISSNHL. Eligible studies evaluated ITC as primary monotherapy, combined initial therapy, or salvage therapy, and reported quantitative audiometric outcomes. Exclusion criteria included non-idiopathic sudden hearing loss, pediatric populations, non-corticosteroid intratympanic therapies, animal or laboratory-only studies, case reports, conference abstracts without full text, duplicate publications, and studies without clinically interpretable hearing outcomes. After screening, 25 studies were included. Salvage ITC provides significant benefit (OR: 6.04; 95% CI: 3.26-11.2; NNT≈3) with Grade A evidence. Combined initial therapy is superior to systemic steroids alone (OR: 2.50; 95% CI: 1.95-3.21), particularly for severe hearing loss. ITC monotherapy is non-inferior to systemic steroids (PTA difference: 2.0 dB). A stratified approach based on treatment timing is recommended. Salvage ITC should be offered to all patients with incomplete recovery. Combined therapy should be considered for patients with severe hearing loss. ITC monotherapy is appropriate when systemic steroids are contraindicated.