Sudden Sensorineural Hearing Loss

Overview

Sudden sensorineural hearing loss (SSNHL) is a rapid loss of hearing that develops over a period of hours to up to about three days, usually affecting one ear. "Sensorineural" means the problem lies in the inner ear (the cochlea) or the nerve that carries sound to the brain, rather than in the outer or middle ear. It is different from the temporary muffled hearing caused by earwax or a cold.

SSNHL is considered a medical emergency. Although it is not life-threatening, the chance of recovering hearing is much better when treatment begins quickly, ideally within the first two weeks and the sooner the better. Many people first notice it on waking, when answering the phone on the affected side, or as a sudden "pop" followed by reduced hearing. In most cases no specific cause is found, but prompt evaluation is important both to start treatment and to rule out the less common but serious underlying conditions.

Symptoms

The defining feature is a rapid drop in hearing, usually in one ear. It is often accompanied by other inner ear symptoms.

• A sudden or rapidly worsening loss of hearing, frequently noticed on waking
• A feeling of fullness or blockage in the affected ear
• Ringing or other noises in the ear (tinnitus)
• Dizziness or a sense of imbalance in some people
• Difficulty understanding speech, especially in noisy settings

Because the chance of recovery depends heavily on starting treatment early, anyone who notices a sudden, unexplained loss of hearing should seek medical care urgently rather than waiting to see if it improves on its own.

Causes

In most people a specific cause is never identified, and the loss is called idiopathic. When a cause is found, it may include:

• Viral infections: Some viral illnesses can damage the inner ear or its nerve.
• Blood flow problems: Reduced circulation to the delicate inner ear.
• Inner ear disorders: Conditions such as Meniere disease.
• Autoimmune disease: The immune system attacking the inner ear.
• Trauma or pressure changes: Head injury or sudden pressure shifts.
• Tumors: Rarely, a benign growth on the hearing and balance nerve (acoustic neuroma) or, uncommonly, certain medications.

Because a small number of cases reflect a serious underlying problem, evaluation usually includes testing to look for treatable causes.

Risk Factors

• Recent viral infection
• Circulation problems and cardiovascular risk factors
• Autoimmune conditions
• Certain inner ear disorders
• Head injury or recent significant pressure changes
• Use of medications known to affect hearing in some cases

Diagnosis

Prompt assessment confirms that the loss is sensorineural and searches for an underlying cause.

• Hearing test (audiogram): The key test to confirm and measure the hearing loss and show it is sensorineural rather than from the outer or middle ear.
• Examination: Checking the ear to rule out simple causes such as wax or fluid.
• MRI scan: Often arranged to look for a tumor on the hearing nerve or other problems, especially with one-sided loss.
• Blood tests: May be done to check for infection, autoimmune, or other contributing conditions.

Treatment

Treatment aims to recover as much hearing as possible and works best when started early. Many people regain some or all of their hearing, though outcomes vary.

• Corticosteroids: The main treatment, usually given as tablets, or sometimes injected directly into the ear (intratympanic), to reduce inflammation in the inner ear.
• Early treatment: Beginning steroids promptly, ideally within the first two weeks, gives the best chance of recovery.
• Treating an underlying cause: If a specific cause such as infection or an autoimmune disorder is found, it is treated directly.
• Hearing rehabilitation: If hearing does not fully recover, hearing aids or other devices can help, and tinnitus management may be offered.

Close follow-up with an ear specialist (otolaryngologist) helps monitor recovery and address any lasting effects.

Prevention

Most cases cannot be prevented because the cause is unknown, but some steps may help.

• Seek care immediately for sudden hearing loss, since early treatment improves recovery
• Manage cardiovascular health, including blood pressure and circulation
• Protect your ears from very loud noise and head injury
• Treat ear and other infections promptly
• Review medications with your doctor if they may affect hearing

When to See a Doctor

Sudden, unexplained hearing loss should be treated as urgent. Seek medical care right away, ideally the same day, if you notice:

• A rapid loss or marked drop in hearing, usually in one ear
• A sudden feeling of blockage with reduced hearing that does not clear
• New ringing or fullness in the ear with hearing loss

Do not wait to see if it improves on its own, because the chance of recovering hearing is much greater when treatment starts early. If hearing loss comes with weakness, facial drooping, slurred speech, or severe imbalance, seek emergency care.

Related Topics

Frequently Asked Questions

References

1. American Academy of Otolaryngology–Head and Neck Surgery. Sudden Sensorineural Hearing Loss.
2. National Institute on Deafness and Other Communication Disorders (NIDCD). Sudden Deafness.
3. Mayo Clinic. Hearing loss — Symptoms and causes.
4. MedlinePlus, U.S. National Library of Medicine. Sudden hearing loss.