Sudden Hearing Loss: What Causes It and Why Treatment Can't Wait - UCSF EARS
Emergency

Sudden Hearing Loss: What Causes It and Why Treatment Can't Wait

Understanding sudden sensorineural hearing loss (SSHL)—causes, why immediate treatment matters, recovery rates, and what to do if you experience sudden hearing changes.

If You're Experiencing Sudden Hearing Loss

This is a medical situation that requires prompt attention. If you've experienced a noticeable drop in hearing within hours to days—especially in one ear—contact a healthcare provider within 24-72 hours for the best treatment outcomes.

Not sure if it's urgent? When in doubt, call. A quick phone conversation can help determine whether you need immediate evaluation or scheduled care.

You wake up one morning and your left ear feels blocked, like you're underwater. You assume it's earwax or congestion from a cold. By afternoon, you realize you can barely hear conversations on that side. By evening, you're worried—but unsure if this warrants urgent medical attention.

This scenario describes sudden sensorineural hearing loss (SSHL)—a medical condition affecting approximately 5-27 people per 100,000 annually in the United States. What makes SSHL different from gradual hearing changes is both the speed of onset and the treatment window: there's a narrow period when intervention works best.

What Is Sudden Sensorineural Hearing Loss?

SSHL is defined as hearing loss of at least 30 decibels across three consecutive frequencies on a hearing test, developing within 72 hours or less. To put 30 decibels in perspective, that's roughly the difference between a whisper and normal conversation volume.

Most commonly, SSHL affects just one ear, though in about 4% of cases both ears are involved. People often first notice it upon waking, when trying to use a phone, or during activities requiring that ear.

What Causes Sudden Hearing Loss?

Here's what makes SSHL particularly challenging: in approximately 85-90% of cases, we never identify a specific cause. These are labeled "idiopathic" sudden hearing loss. However, research has identified several likely mechanisms.

Viral Infections

Viral infections are believed to cause roughly 10-15% of identifiable SSHL cases. Viruses associated with sudden hearing loss include Herpes simplex, Varicella-zoster, Influenza, and COVID-19.

Vascular Problems

Blood flow disruption to the inner ear can cause sudden hearing loss. The inner ear requires constant, uninterrupted blood supply. Conditions like diabetes, hypertension, or blood clots can interrupt this supply.

How Doctors Investigate the Cause

Your evaluation typically includes:

  • Hearing test (audiogram): To differentiate between nerve loss vs. blockage.
  • Blood tests: Checking for infection and autoimmune markers.
  • MRI scan: To rule out acoustic neuroma (tumor) or structural issues.

Why Treatment Timing Matters

This is the critical piece of information about SSHL: there's a limited window when treatment is most effective—typically within the first 72 hours to 2 weeks after onset.

Treatment Timing Recovery Likelihood
Within 72 hours Best outcomes - significantly improved recovery rates
Within 1-2 weeks Good outcomes - treatment still beneficial
2-4 weeks Moderate outcomes - some benefit possible
After 4 weeks Limited outcomes - recovery unlikely but occasionally seen

What Treatment Looks Like

The standard treatment for SSHL involves corticosteroids, which reduce inflammation in the inner ear. Treatment approaches include:

Oral Steroids

Typically a high dose of prednisone for 1-2 weeks, often using a "blast and taper" approach.

Intratympanic Steroid Injections

If oral steroids are ineffective or medically unsafe for you, doctors may inject steroids directly through the eardrum into the middle ear space. This delivers high concentrations of medication directly to the inner ear.

Important Note About Spontaneous Recovery

Between 32-65% of people with SSHL experience some spontaneous recovery even without treatment. However, treatment consistently shows better outcomes than no treatment, particularly for complete recovery.

What Recovery Looks Like

Recovery outcomes vary significantly. With treatment, approximately 30-35% experience complete recovery, while another 30-35% see partial improvement.

Factors associated with better recovery: Younger age, milder initial hearing loss, absence of vertigo, and early treatment (within 7 days).

The Bottom Line

While SSHL is frightening, many people recover substantial hearing—especially with prompt treatment. Even those who don't fully recover have excellent rehabilitation options available.

Common Questions About Sudden Hearing Loss

How do I know if my hearing loss needs urgent attention?

Seek urgent evaluation (within 72 hours) if you experience noticeable hearing loss developing within 72 hours or less, especially in one ear, or if accompanied by fullness/pressure. Gradual loss over months is usually not an emergency.

Can I wait to see if it gets better on its own?

Waiting significantly reduces treatment effectiveness. The critical treatment window is within 72 hours to 2 weeks. Think of it like a stroke: early intervention dramatically improves outcomes.

Should I get an MRI right away?

Not necessarily immediately—treatment shouldn't wait for imaging. Most doctors start steroids first, then order an MRI within several weeks to rule out structural causes like tumors.

Experiencing Sudden Hearing Changes?

If you're experiencing sudden hearing loss, our emergency care guide explains when and where to seek help, what to expect during evaluation, and how to access urgent appointments.

View Emergency Care Guide