Sudden Sensorineural Hearing Loss (SSNHL) is a rapid and unexplained loss of hearing, typically in one ear, that occurs over a period of 72 hours or less. It is considered an urgent medical emergency.
- Symptoms include a sudden drop in hearing, a feeling of fullness or pressure in the ear, ringing in the ear (tinnitus), and sometimes dizziness or vertigo.
- Causes are often unknown (idiopathic), but can be linked to viral infections, autoimmune conditions, vascular problems, head trauma, or certain medications.
- Diagnosis involves an urgent hearing test called Pure Tone Audiometry to confirm a significant hearing loss and other checks to rule out issues like earwax buildup.
- Treatment is most effective when started within 24-48 hours. The primary treatment is high-dose corticosteroids, which can be given orally or by injection.
- Prognosis: With timely treatment, about one-third of people recover fully, one-third recover partially, and one-third experience no recovery. If permanent hearing loss remains, audiological rehabilitation and hearing aids are options.
Sudden hearing loss can be alarming — and for good reason. If you or someone you know wakes up with a muffled or blocked ear that doesn’t clear, it could be Sudden Sensorineural Hearing Loss (SSNHL), a serious condition that demands urgent medical attention.
SSNHL isn’t just a minor inconvenience. It’s considered an audiological emergency, and timely diagnosis and treatment can significantly affect outcomes.
What Is Sudden Sensorineural Hearing Loss (SSNHL)?
SSNHL refers to a rapid, unexplained loss of hearing, typically in one ear, occurring over a period of 72 hours or less. It’s caused by damage to the hearing organ (cochlea) or the auditory nerve, rather than an issue related to the ear canal or the mechanism between the eardrum and cochlea.
This condition is often mistaken for earwax buildup, an ear infection, or even a blocked Eustachian tube. However, unlike these more benign issues, SSNHL can result in permanent hearing loss if not treated promptly.
Key Symptoms of SSNHL
People with SSNHL often describe it as waking up and suddenly being unable to hear in one ear — as though the ear has been “switched off.” Symptoms include:
- Sudden loss of hearing in one ear (rarely both)
- A sensation of fullness or pressure in the ear
- Tinnitus (ringing or buzzing sounds)
- Vertigo or dizziness
- Difficulty understanding speech in noisy environments
Important: If you notice a sudden drop in hearing, especially in one ear, seek medical attention immediately — ideally within 24 to 48 hours.
What Causes SSNHL?
In around 85–90% of cases, the exact cause of SSNHL remains idiopathic, meaning it’s unknown. However, research has identified several potential causes:
- Viral infections: (e.g., herpes simplex, influenza)
- Autoimmune conditions: Whereby one's immune system can attack the hearing organ, the cochlea, or associated parts of the auditory pathway.
- Vascular events: Such as a small stroke in the auditory pathway, affecting blood supply.
- Head trauma: Including severe barotrauma. Learn more about ear pain from pressure changes and barotrauma here.
- Neurologic diseases: Such as multiple sclerosis.
- Ototoxic medications: Medications which can damage the hearing organ, the cochlea, such as chemotherapy drugs.
- Acoustic Neuroma: A benign tumour which can affect the nerve responsible for sound.
Diagnosis: How Is SSNHL Identified?
Diagnosis of SSNHL involves both clinical assessment and urgent hearing tests:
- Case History & Symptom Check: Your audiologist or doctor will ask when the hearing loss began and about any accompanying symptoms.
- Pure Tone Audiometry: This urgent hearing test confirms a drop of at least 30 decibels over three connected frequencies within 72 hours — the diagnostic criteria for SSNHL.
- Tympanometry & Middle Ear Checks: To rule out non-sensorineural hearing issues like earwax or middle ear infection.
- MRI Scans (if needed): To exclude serious underlying causes like acoustic neuroma or other nerve lesions.
Prompt referral from a GP or audiologist to an Ear, Nose, and Throat (ENT) specialist is often required, especially in urgent or severe cases. Where to Get Help: Start by contacting your GP for an urgent assessment.
Treatment: Why Time Matters
The sooner SSNHL is treated, the better the outcome. Treatment ideally begins within 24–48 hours of symptom onset.
Common treatments include:
- High-dose corticosteroids: Administered orally or injected directly through the eardrum (intratympanic injection) to reduce inner ear inflammation. This is the primary and most effective treatment.
- Antiviral medications: If a viral cause is strongly suspected.
- Hyperbaric oxygen therapy: Access to this treatment is limited in NZ and is less commonly used than steroids.
- Audiological rehabilitation and hearing aids: If permanent hearing loss remains after treatment.
According to studies (including those cited in reputable journals like The Lancet and PubMed), about one-third of people recover fully, one-third recover partially, and one-third experience no recovery — underscoring the critical importance of urgent care.
FAQ: Sudden Sensorineural Hearing Loss (SSNHL)
Answers to our most asked questions related to Sudden Sensorineural Hearing Loss
Sudden Sensorineural Hearing Loss (SSNHL) is a rapid, unexplained hearing loss, typically in one ear, occurring within 72 hours. It’s an emergency because early treatment (ideally within 48-72 hours) with corticosteroids can significantly improve recovery chances and prevent permanent hearing damage. Unlike a blocked ear or infection, SSNHL involves damage to the inner ear or nerve, which requires urgent medical intervention.
SSNHL is usually painless, doesn't cause fever, and isn't typically associated with cold symptoms (though viral infections can be a cause). If your hearing drops suddenly and dramatically, especially and there's no relief after trying to clear your ear (like yawning or swallowing), it's time to see a doctor urgently. Whilst not true for all cases, some people who have confirmed SSNHL recall a loud audible “pop” just as the hearing dropped, and others often first notice their ear is unexpectedly deafened after waking up from sleep.
Multiple medical studies and clinical guidelines consistently show that early treatment with corticosteroids, particularly within the first 72 hours of symptom onset, significantly improves recovery rates for SSNHL. Delays beyond this window sharply reduce the chance of regaining hearing.
Yes. If you experience sudden hearing loss, you should immediately contact your GP. They will typically refer you for an urgent audiology test and, if SSNHL is confirmed, to an ENT (Ear, Nose, and Throat) specialist. Treatment (usually oral or intratympanic steroids) is often initiated quickly due to the urgency.
No. With timely and appropriate treatment, many people regain some or all of their hearing. However, some individuals may have lasting hearing loss, especially if treatment is delayed, the loss is profound, or there are specific underlying causes. Even with residual loss, effective management and support options are available.
