What causes sudden hearing loss in one ear?

Sudden hearing loss in one ear can range from a simple ear wax blockage or infection to sudden sensorineural hearing loss (SSHL), which needs prompt medical attention. If your hearing drops suddenly, or you have ear pain, discharge or dizziness, contact your GP urgently or attend an emergency department the same day. Early treatment gives the best chance of a good outcome.

What are the common causes of sudden hearing loss in one ear?

• Ear wax blockage. A sudden build-up or shift of wax can quickly reduce hearing in one ear, often with a feeling of fullness.
• Ear infection. Middle or outer ear infections can cause fluid build-up and rapid, temporary hearing changes, sometimes with pain.
• Fluid behind the eardrum, often linked to a cold, allergies or sinus congestion.

These causes are usually treatable once identified, and hearing often returns once the underlying issue resolves.

Sudden sensorineural hearing loss (SSHL)

SSHL is an unexplained, rapid drop in hearing in one ear. It is often noticed within hours or a few days, sometimes on waking. It is considered a medical emergency. Prompt treatment, often with steroids, usually within a short treatment window of the first days, gives the best chance of recovery. It is different from gradual, age-related hearing loss.

Why does sudden hearing loss in one ear need urgent attention?

The cause of sudden one-sided hearing loss cannot be determined from symptoms alone. SSHL also responds best to early treatment. So any sudden hearing change should be treated as urgent, rather than something to monitor for a few weeks. The treatment window is short.

What should you do?

If your hearing changes suddenly, or you have ear pain, discharge or dizziness, contact your GP urgently or attend an emergency department the same day. Once any urgent medical cause has been assessed and treated, a hearing test can confirm your hearing status and guide any further care, including with an audiologist.

For more information, visit Healthdirect (healthdirect.gov.au) (opens in a new tab).

Sources: Healthdirect; Mayo Clinic. Information current July 2026 and general in nature.