I woke up with a blocked, muffled ear — is it just wax?

Possibly, but do not assume so. Sudden hearing loss in one ear can be sensorineural, which is time-critical. See a doctor urgently — the same day or within a couple of days — so the cause can be checked with an ear exam and hearing test.

How quickly do I need to be treated?

As soon as possible. Corticosteroids work best when started within days, and generally within the first two weeks. The sooner treatment begins, the better the chance of recovery.

Will my hearing come back?

It varies. Some people recover fully, some partially, and some not at all. Early treatment gives the best chance, and your ENT specialist can give a clearer outlook after the hearing test.

Why do I need an MRI?

To exclude a benign tumour on the hearing nerve (acoustic neuroma) or other rare causes behind the inner ear. It is found in only a small percentage of cases, but it is important to rule out.

What are the steroid injections into the ear?

Intratympanic steroid injection delivers medicine directly through the eardrum into the middle ear, near the inner ear. It is used first-line alongside or instead of tablets, and as a rescue treatment if tablets do not help or are not suitable (for example in diabetes).

Sudden Hearing Loss: An Ear Emergency

Written & reviewed by the BestDoctors.sg editorial team · Last updated 1 Sep 2026 · General information, not medical advice

Quick answer. Sudden sensorineural hearing loss is a rapid, unexplained loss of hearing – usually in one ear – developing over hours to a few days, from a problem in the inner ear or hearing nerve. It is a medical emergency: treatment works best when started early (within days), so it must never be brushed off as ear wax or a cold. Many people first notice it on waking, sometimes with ear fullness, ringing (tinnitus) or dizziness. Most cases have no cause found, but a few point to something important. Anyone with sudden hearing loss in one ear should see a doctor urgently – the same day or within a few days.

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In a medical emergency, or for severe or sudden symptoms such as breathing difficulty, chest pain, fainting or stroke signs, call 995 immediately.

The single most important message here is speed. Sudden hearing loss is one of the few ear problems where waiting even a week can change the outcome – so it is worth treating as an emergency, not a wait-and-see.

This is a medical emergency — act fast. Sudden hearing loss in one ear (or both) means you should see a doctor or go to A&E the same day. The treatment that gives the best chance of recovery works only within a short window — ideally the first few days, and generally within the first two weeks. Do not wait to see if it clears on its own and do not assume it is only wax or a cold. Call 995 immediately if hearing loss comes with stroke signs: face drooping, arm or one-sided weakness, slurred speech, or severe imbalance.

What it is

Sudden sensorineural hearing loss (SSNHL) is a rapid loss of hearing, usually in one ear, that comes on over hours to a few days. It is caused by damage or dysfunction in the cochlea (the hearing organ of the inner ear) or in the hearing nerve that carries sound signals to the brain – the “sensorineural” pathway. Doctors define it as a clear drop in hearing sensitivity across several test frequencies, developing quickly (typically within three days). Many people wake up with it, or notice it suddenly when they put a phone to the affected ear or try to use earphones.

This differs from conductive hearing loss, where sound is simply blocked on its way in by ear wax, fluid behind the eardrum, or an ear infection. Conductive problems are usually reversible and rarely urgent. Because SSNHL involves the delicate inner ear or nerve, the longer it is left untreated, the more likely the loss becomes permanent – so the two must be told apart quickly, and sudden loss is never something to “sleep on”.

Why it is urgent — act the same day

There is a limited window in which treatment can help. Recovery is best when treatment begins within days of the loss, and generally within the first two weeks; after that, the chance of meaningful improvement falls sharply. This is the key reason SSNHL is treated as an emergency rather than a routine ear complaint. If you notice a sudden drop in hearing, arrange to be seen the same day – through a GP who can refer you urgently, an ENT (ear, nose and throat) specialist, or a hospital A&E if you cannot get an appointment quickly. It is far better to be assessed and reassured than to lose the treatment window.

Symptoms

The main feature is a sudden reduction in hearing in one ear, often first noticed on waking or when using a phone or earphones. Alongside this, people commonly describe:

a blocked, “full” or pressured feeling in the ear, as if it needs to “pop”;
ringing, buzzing or roaring in the ear (tinnitus), which often appears at the same time;
sounds seeming distorted, muffled or unusually harsh;
difficulty telling where sounds are coming from, or trouble following conversation in a group;
sometimes dizziness or a spinning sensation (vertigo) and a feeling of imbalance.

Because the fullness and blocked feeling can mimic a wax build-up or a lingering cold, many people delay seeking help. If in doubt, treat it as urgent and get the ear examined – a simple check can distinguish a harmless blockage from a true nerve-type loss that needs fast treatment.

Causes

In the large majority of cases no cause is ever found, and the condition is labelled idiopathic. When a cause is identified, recognised ones include:

Viral infections – thought to affect the inner ear or hearing nerve;
Inner-ear or circulation problems – reduced blood flow to the cochlea, which has a very delicate blood supply;
Certain medicines that can be toxic to the inner ear (ototoxic drugs);
Autoimmune conditions, where the body’s immune system affects the inner ear;
Head injury or pressure changes affecting the inner ear;
Importantly, occasionally a tumour on the hearing nerve (an acoustic neuroma), which is non-cancerous but needs to be found and monitored;
Rarely, a stroke or problem with blood vessels supplying the brainstem – especially when hearing loss comes with severe dizziness, slurred speech or weakness.

Reversible causes such as wax or fluid should always be excluded first, but a genuine sensorineural sudden loss needs urgent ENT review whether or not a cause is obvious.

How it is diagnosed

The first job is to confirm that this really is a nerve-type (sensorineural) loss rather than a simple blockage. The doctor will examine the ear to look for wax, fluid or infection, and arrange hearing tests urgently. A pure-tone audiogram measures how well each ear detects sounds across a range of pitches and confirms whether the loss is sensorineural and how severe it is; tuning-fork tests at the bedside can give an early clue while formal testing is arranged.

Once a sensorineural loss is confirmed, an MRI scan is usually arranged to look for an underlying cause – in particular an acoustic neuroma on the hearing nerve, or, less commonly, a problem in the brain or its blood vessels. Blood tests may be done to look for infection, autoimmune or other conditions. Importantly, waiting for a scan should not delay starting treatment – the two happen in parallel, because the treatment window is short.

Why timing matters

SSNHL is unusual among ear conditions because how quickly you are treated strongly affects the result. The inner ear does not tolerate prolonged injury well, so the benefit of treatment is greatest when it starts within the first days and diminishes over the following weeks. Someone treated on day one or two generally has a better chance of recovery than someone treated after two or three weeks – which is why same-day care can be the difference between recovering and being left with permanent loss.

Treatment

The mainstay of treatment is steroids (corticosteroids), aimed at reducing inflammation in the inner ear. These can be given as:

Tablets taken by mouth over a short, tapering course; and/or
Injections through the eardrum (intratympanic injections), which deliver the steroid directly to the inner ear. This route is often used when tablets are unsuitable – for example in poorly controlled diabetes – or as a “salvage” option when tablets have not helped.

Steroids are most effective when started as soon as possible – ideally within the first days to a couple of weeks. Beyond the steroids themselves, treatment also means treating any identified cause (for instance addressing an infection, reviewing an ototoxic medicine, or managing an autoimmune condition). If a tumour such as an acoustic neuroma is found, it is managed separately, usually with monitoring or specialist treatment.

Where hearing does not fully recover, the focus shifts to supporting hearing: rehabilitation, strategies for communication, and hearing aids or other devices where appropriate. An ENT specialist and audiologist can advise on what will help most for the level of loss that remains.

Living with it and outlook

Outcomes vary widely. Some people recover fully, some partially, and some not at all – and there is no way to predict the outcome for an individual at the start. What is consistent is that earlier treatment gives the best chance of recovery, which is why same-day assessment matters so much. Where some loss persists, hearing aids, assistive listening devices and rehabilitation can make a real difference to everyday life. Persistent tinnitus or dizziness can also be managed with specific therapies, and ongoing follow-up with an ENT specialist helps track recovery and support you if the loss turns out to be lasting.

When to see a doctor

See a doctor urgently – the same day – if you notice a sudden drop in hearing in one or both ears, even if it seems to be just a blocked or full feeling. In Singapore you can see a GP for an urgent ENT referral, go directly to an ENT specialist, or attend a hospital A&E if you cannot be seen quickly; reliable general information is also available on HealthHub. Do not wait to see whether it clears on its own – the treatment that gives the best chance of recovery works only if it is started early.

Emergency reminder. Sudden hearing loss in one (or both) ears is a medical emergency — see a doctor or go to A&E the same day, because prompt treatment within days gives the best chance of recovery. Call 995 if hearing loss comes with stroke signs — face drooping, arm or one-sided weakness, slurred speech, or severe imbalance — or with sudden severe vertigo, a bad headache or double vision.

Related ear, nose & throat conditions

Sources

AAO-HNS clinical practice guideline (via NCBI) — definition of sudden sensorineural hearing loss and the time-critical treatment window.
NHS — sudden hearing loss in one or both ears needs urgent attention.
Mayo Clinic — sensorineural versus conductive hearing loss; when to seek care.
NCBI — corticosteroid treatment (oral and intratympanic) for idiopathic sudden sensorineural hearing loss.

General information only. This guide is general information about an ear, nose or throat condition and is not a diagnosis or personalised medical advice. See a doctor — a GP or an ENT specialist — for assessment, tests and treatment. Sudden hearing loss in one ear should be seen urgently, and call 995 for sudden severe vertigo with a bad headache, slurred speech, double vision or one-sided weakness.

Sudden Hearing Loss in Singapore