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Sudden sensorineural hearing loss
Other Resources UpToDate PubMed

Sudden sensorineural hearing loss

Contributors: Matthew Kubina, Paul C. Bryson MD, MBA
Other Resources UpToDate PubMed


Sudden sensorineural hearing loss (SSNHL) is defined as sensorineural hearing loss (SNHL) of at least 30 decibels (dB) over at least 3 contiguous audiometric frequencies that occurs within a 72-hour period. The hearing loss is most commonly unilateral, with bilateral involvement occurring less commonly. This condition often occurs without an identifiable etiology, although some proposed mechanisms, such as microvascular, immune, or infectious causes, have been identified. Approximately 10% of patients will have a specific cause identified, but the majority of patients are diagnosed with idiopathic SSNHL.

This condition has an incidence of approximately 5-30 cases per 100 000 per year. It affects males and females equally, with individuals aged 50-60 years most commonly affected. Potential risk factors include cardiovascular disease and autoimmune conditions.

Prognosis for these patients is generally good. Complete or partial recovery occurs in approximately two-thirds of affected patients. However, those without any changes over a 2-week period are less likely to recover. The presence of vestibular dysfunction, more severe hearing loss, and increased time between onset and treatment are all factors that can indicate a worse prognosis.

Limited reports of hearing loss, including sudden cases, have been documented in association with Pfizer-BioNTech, Moderna, and AstraZeneca shots, as well as COVID-19. These reports suffer from a number of limitations including recall bias, nocebo effect, and survey methodology. Causality has not been determined and studies that include control groups, audiometric data, and more accurate patient reporting are needed. A plausible mechanism of action involving the vestibulocochlear nerve has been suggested if causality is ultimately proven.


H91.20 – Sudden idiopathic hearing loss, unspecified ear

715239002 – Sudden sensorineural hearing loss

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Diagnostic Pearls

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Differential Diagnosis & Pitfalls

  • Conductive hearing loss (CHL; eg, otosclerosis, cerumen buildup) – Initial otoscopic examination and Weber and Rinne tests aid in ruling out these conditions.
  • Vestibular schwannoma – Mass can be visualized with MRI.
  • Cogan syndrome – Bilateral SNHL with vestibular symptoms and inflammatory ocular manifestations.
  • Tympanic membrane perforation or other trauma
  • Multiple sclerosis flare
  • Transient ischemic attacks (eg, anterior inferior cerebellar artery occlusion) – Accompanying weakness or other neurologic symptoms would likely be present.
  • Meniere disease – Tinnitus, vertigo, and aural fullness will be present.
  • Ototoxic medication exposure (eg, aminoglycosides, loop diuretics, salicylates) – See Drug-induced ototoxicity.

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Last Reviewed:03/27/2022
Last Updated:05/09/2022
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Sudden sensorineural hearing loss
A medical illustration showing key findings of Sudden sensorineural hearing loss : Hearing loss, Tinnitus, Vertigo
Copyright © 2024 VisualDx®. All rights reserved.