Sudden Sensorineural Hearing Loss: Recognising an ENT Emergency
A community pharmacy triage guide to recognising sudden sensorineural hearing loss, distinguishing it from wax or infection, and acting within the critical treatment window.
Why this matters
Sudden sensorineural hearing loss (SSNHL) is an otological emergency. It is defined as hearing loss developing over three days or less that cannot be explained by a problem in the outer or middle ear. NICE guidance (NG98, 2018) classifies it as an emergency requiring immediate specialist referral: the person should be seen by an ear, nose and throat (ENT) specialist within 24 hours if the loss developed within the past 30 days.
Community pharmacists are often the first point of contact. The problem is that sudden sensorineural hearing loss looks, at first, exactly like a blocked ear. The patient says their ear feels full, muffled, or blocked. They may have already tried warm water or wax softening drops with no improvement. The pharmacist who recommends further ear drops and a follow-up in a week has potentially closed the treatment window. Steroids started within 72 hours of onset offer the best chance of hearing recovery. Beyond two weeks, steroid treatment is considered unlikely to help.
The most common presentation is unilateral: the patient wakes up and cannot hear in one ear, or notices sudden loss during the day. It is frequently accompanied by tinnitus (ringing, buzzing, or roaring in the affected ear) and a sense of aural fullness. There is usually no pain and no discharge. A clear cause is found in fewer than 15% of cases: the majority are idiopathic. However, the differential diagnosis includes posterior circulation stroke, vestibular schwannoma, autoimmune disease, and ototoxic medicines, making prompt specialist assessment essential.
Red flags vs more likely benign
| Feature | More likely benign | Red flag ⚠ |
|---|---|---|
| Speed of onset | Gradual reduction in hearing over weeks or months | Hearing loss developing over three days or less, or noticed on waking: sudden onset is the defining feature of this emergency |
| Ear affected | Both ears equally affected, consistent with wax or middle ear fluid | One ear only, sudden: unilateral sudden hearing loss should be treated as SSNHL until specialist assessment proves otherwise. Bilateral sudden hearing loss is rare and requires immediate specialist assessment. |
| Tinnitus | Absent, or mild bilateral hiss unrelated to hearing change | New ringing, buzzing, or roaring in the affected ear at the same time as the hearing loss: a consistent feature of SSNHL |
| Response to wax treatment | Hearing improves after wax softening drops or irrigation | No improvement despite attempted wax treatment, or no wax visible: do not continue wax treatment. Refer urgently. |
| Pain or discharge | Ear pain, itching, or discharge: suggests otitis externa or otitis media | No pain and no discharge: sudden hearing loss without these features points away from infection and towards SSNHL |
| Dizziness or vertigo | Mild lightheadedness unrelated to the ear | True spinning vertigo or dizziness alongside sudden hearing loss: warrants same-day urgent assessment, as posterior circulation stroke must be excluded |
| Neurological symptoms | None | Facial weakness, slurred speech, arm weakness, double vision, difficulty swallowing, or severe vertigo alongside sudden hearing loss: call 999 immediately. These may indicate stroke. |
Think Sudden Hearing Loss if Your Patient Says...
These phrases should immediately redirect the consultation away from wax management and towards urgent referral.
- "I woke up this morning and I could not hear out of my right ear."
- "My ear has gone very muffled very suddenly, almost overnight."
- "I have a constant ringing in my left ear and the hearing is much worse."
- "I tried ear drops for a few days but nothing has changed."
- "There is no wax there but I feel like my ear is completely blocked."
- "The hearing loss came on at the same time as dizziness."
A patient who describes sudden or overnight hearing loss in one ear with no pain, no discharge, and no response to wax treatment should be referred for same-day ENT assessment, not offered further ear products.
Causes and High-Risk Groups
Understanding the causes helps the pharmacist identify who is at greater risk and ask the right questions.
- Idiopathic: no identifiable cause is found in up to 85 to 90% of cases. Idiopathic SSNHL is the most common diagnosis and is still treated with steroids as an emergency.
- Posterior circulation stroke: sudden hearing loss with vertigo, facial weakness, or other neurological symptoms should be treated as a possible stroke until excluded. The anterior inferior cerebellar artery (AICA) supplies the inner ear, and its territory strokes can present with sudden unilateral hearing loss.
- Vestibular schwannoma (acoustic neuroma): usually causes progressive unilateral hearing loss and tinnitus, but can occasionally present as sudden loss. An MRI is part of the specialist workup.
- Ramsay Hunt syndrome: herpes zoster reactivation affecting the facial nerve. Look for vesicles in or around the ear canal alongside sudden hearing loss and facial weakness.
- Ototoxic medicines: aminoglycosides (systemic use) and platinum-based chemotherapy (cisplatin, carboplatin) carry the highest risk of sudden hearing change and warrant same-day ENT contact if a patient on these reports new hearing loss. High-dose loop diuretics and quinine are also associated with hearing effects. High-dose salicylates typically cause reversible tinnitus rather than classic SSNHL, but any new hearing change on these medicines should still prompt review.
- Autoimmune inner ear disease: rare, may cause bilateral or fluctuating sudden hearing loss. Responds well to steroids if treated promptly.
Ramsay Hunt syndrome requires antiviral treatment alongside steroids and should not be missed. If vesicles are visible in or around the ear alongside facial weakness and hearing loss, the GP must be contacted the same day.
What to do in pharmacy
Key takeaways
- Sudden hearing loss developing over three days or less is an otological emergency: NICE requires ENT assessment within 24 hours, not a week of ear drops.
- Steroids started within 72 hours of onset offer the best chance of recovery. Do not close this window by recommending wax treatment and a review appointment.
- Sudden hearing loss with facial weakness, slurred speech, arm weakness, double vision, difficulty swallowing, or severe vertigo may indicate stroke: call 999.