01OverviewDefinition, clinical context and the essential points that orientate the chapter.
Sudden sensorineural hearing loss is an urgent presentation because the opportunity for treatment may diminish with time and because some patients have an underlying neurological, inflammatory or structural disorder. Many cases remain idiopathic after assessment. The term should follow a reasoned evaluation rather than simply describe any sudden blocked ear. The absence of pain or an abnormal tympanic membrane does not make an acute loss benign.
The conventional audiometric description is a sensorineural decline of at least 30 dB across three consecutive frequencies within 72 hours. This helps characterise cases but should not become a barrier to urgent clinical care when an audiogram is unavailable, the previous threshold is unknown or the decline falls outside a research definition. ENT UK explicitly allows clinical discretion for less marked loss or a longer interval. The practical referral decision begins with the history and examination.
Patients may notice the problem on waking, when using a telephone or when covering the better ear. Tinnitus and a sense of pressure can accompany the loss; dizziness may also occur. Ask about preceding hearing, infections, medications, noise or blast exposure, trauma and autoimmune symptoms. A detailed neurological history and examination is especially important when imbalance is severe or there are facial, sensory, visual or limb findings.
Treatment discussions need to acknowledge uncertainty. Recovery varies, some improvement can occur without treatment and steroids carry meaningful risks. At the same time, delaying an indicated ENT assessment while trying decongestants or repeated wax treatment can lose time. Give a clear explanation of the suspected mechanism, the referral urgency and the reason for considering early steroid therapy, then document the patient's preferences and the agreed plan.
Key points
- Ask when hearing was last normal, how many days deterioration took and how long the patient waited before presenting.
- NICE distinguishes sudden loss within the past 30 days from older sudden loss and progression over four to 90 days.
- Exclude a convincing conductive cause with history and otoscopy, but do not let incidental wax or fullness falsely explain the presentation.
- NICE advises considering a steroid for idiopathic adult sudden sensorineural loss; it does not prescribe a specific dose schedule.
- NHS Highland uses oral prednisolone 1 mg/kg daily, maximum 60 mg, for seven days followed by tapering during the next week, preferably starting in the first week.
- Arrange audiometric follow-up, investigation of possible causes and access to hearing rehabilitation or tinnitus support when impairment persists.
02AetiologyUnderlying causes, associations and risk factors, with why each one matters.
Idiopathic sudden cochlear dysfunction
A cause is not identified in many patients despite appropriate evaluation. Proposed inflammatory or vascular mechanisms do not establish the diagnosis in an individual, and the label should follow assessment for alternative explanations.
A specific otological or systemic cause
Trauma, infection, autoimmune disease, drug toxicity and retrocochlear pathology can produce acute sensory hearing impairment. Associated symptoms and exposure history determine which directed investigations are appropriate.
A neurological presentation
Acute hearing change can accompany a central neurological disorder, including stroke. Focal examination findings or a concerning combination of vestibular and neurological symptoms should redirect assessment to the relevant emergency pathway.
03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.
- 1Impaired conversion or neural transmission
Cochlear sensory dysfunction or injury along the auditory pathway can abruptly reduce hearing despite an intact external and middle ear. Air- and valid bone-conduction thresholds are therefore affected without a sufficient conductive gap to explain the loss.
- 2Time-dependent recovery potential
Some acute dysfunction may improve, while established injury can leave a lasting deficit. This underlies the emphasis on early specialist assessment and treatment discussion, although an individual patient's recovery cannot be promised.
- 3A normal drum with important disease
The tympanic membrane represents the sound-transmission system rather than cochlear function. Its normal appearance is compatible with a severe sensory deficit and should not outweigh a convincing account of abrupt loss.
04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.
A decline over no more than three days is sudden; the time elapsed since that event is a separate variable. NICE requires assessment within 24 hours when it occurred in the last 30 days, but within two weeks when it occurred more than 30 days ago.
Look for impacted wax, acute infection, a perforation or vesicles, and decide whether any finding genuinely explains the loss. Record an unobstructed normal drum explicitly. Use tuning-fork results as supplementary evidence, recognising that severe asymmetry can produce cross-hearing.
Assess facial movement and sensation, relevant cranial nerves and other findings suggested by the presentation. Ask about inflammatory symptoms, recurrent episodes and systemic illness. Trauma or suspected stroke needs the appropriate specialty rather than a routine idiopathic-loss pathway.
Review diabetes, active infection, severe mood disorder or previous steroid psychosis, peptic ulceration, hypertension, glaucoma and current medicines. Existing systemic steroid exposure affects withdrawal planning. High risk should prompt urgent ENT discussion about the safest treatment approach, not abandonment of assessment.
05InvestigationsWhat to request, why it matters and how to interpret it.
Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.
- 01
Immediate clinical assessment and referralFirst step - Why
- Recognise a sensory presentation and exclude emergencies without avoidable delay.
- Interpretation and limitations
- The clinical history can justify referral before audiometry. A loss worsening over four to 90 days needs urgent assessment within two weeks under NICE, distinct from the recent sudden-loss category. Communicate the actual dates and the interval of deterioration.
- 02
Urgent pure-tone audiometry - Why
- Confirm and quantify the sensory deficit and provide a baseline.
- Interpretation and limitations
- Use appropriately masked thresholds where needed. Testing establishes severity and configuration and allows an objective comparison after treatment. If not immediately available, make the referral and agree how the urgent audiogram will be obtained.
- 03
MRI of the internal auditory meati - Why
- Investigate a possible retrocochlear or other structural cause.
- Interpretation and limitations
- ENT UK includes internal-auditory-meatus MRI in the assessment of idiopathic unilateral sudden loss. Localising signs independently justify offering MRI under NICE. Investigation and early treatment can proceed in parallel; waiting for routine MRI should not postpone time-sensitive management.
- 04
Directed laboratory and systemic assessment - Why
- Investigate a suspected specific cause or prepare for safer treatment.
- Interpretation and limitations
- Clinical features suggesting autoimmune or infectious disease guide additional tests and specialist input rather than an indiscriminate panel for every patient. Baseline glucose and other relevant observations help plan steroid monitoring in someone at increased treatment risk.
06Differential diagnosisRealistic alternatives and the features that help distinguish them.
Wax or middle-ear transmission loss
Obstruction, fluid or infection may account for an acute hearing complaint when examination and severity agree. Small incidental wax deposits should not be accepted as the explanation for a large sudden unilateral deficit.
A focal neurological emergency
Stroke or another acute central disorder becomes more concerning with focal deficits or a major neurological syndrome. Assessment must address that possibility promptly rather than treating every normal-drum hearing loss as idiopathic.
Fluctuating or rapidly progressive disease
A course evolving over several days to months, recurrent episodes or associated systemic features may indicate another inner-ear or inflammatory disorder. The exact chronology changes referral categorisation and subsequent investigation.
07ManagementImmediate care, first-line treatment, alternatives and escalation.
01A recent suspected idiopathic lossArrange prompt assessment and discuss treatmentFirst stepHearing deteriorated abruptly and examination gives no adequate conductive explanation.+
- 1Apply the NICE immediate referral category when onset was within the previous 30 days and deterioration took three days or less, seeking assessment within 24 hours.
- 2Discuss oral steroid benefits, uncertainty and contraindications with ENT and the patient, ideally early in the first week, using a clearly documented selected regimen.
- 3Arrange the initial audiogram, appropriate investigation and a named follow-up plan rather than treating the prescription as completion of care.
02A steroid regimen agreed with ENTPrescribe the course and withdrawal schedule togetherThe adult chooses systemic treatment after a risk assessment and the treating team agrees it is appropriate.+
- 1The NHS Highland regimen is oral prednisolone 1 mg/kg daily, capped at 60 mg, for seven days with tapering during the following week; calculate the starting dose from weight.
- 2For an adult receiving the 60 mg maximum, the published ENT UK example gives 60 mg on days one to seven, then 50, 40, 30, 20 and 10 mg on successive days, stopping on day 13. Lower starting doses or existing steroid exposure require an individual written reduction plan.
- 3Give administration and adverse-effect advice, arrange risk-based monitoring and ensure that any concurrent long-term steroid requirement is not inadvertently stopped.
03Limited recovery or systemic treatment unsuitableReview promptly for further treatment and rehabilitationThere is little improvement, delayed presentation or an important systemic steroid contraindication.+
- 1Discuss the patient promptly with ENT, including consideration of intratympanic steroid treatment; NHS Highland specifically advises this discussion after the first week or when systemic steroids are contraindicated.
- 2Repeat audiometry after the initial course; the ENT UK pathway uses approximately 10–14 days to assess early response and consider salvage treatment.
- 3Explain options for persistent hearing impairment and tinnitus, ensuring that appropriate imaging and investigation are completed alongside rehabilitation.
Key medicines and prescribing safety1 treatment · regimens, roles and cautions+
Prednisolone for an agreed idiopathic sudden-loss course
Orally 1 mg/kg once daily, maximum 60 mg daily, for seven days, followed by an agreed taper during the next week. For a starting dose of 60 mg, the ENT UK example is 50 mg on day 8, 40 mg on day 9, 30 mg on day 10, 20 mg on day 11 and 10 mg on day 12, then stop on day 13. Individualise the written taper for a lower starting dose or prior systemic steroid use.Take with or after food, usually in the morning. Systemic infection without appropriate anti-infective treatment and ocular herpes simplex are contraindications in the cited SmPC. Assess diabetes, psychiatric history, ulcer disease, hypertension, glaucoma and interactions; arrange glucose monitoring where needed. Seek urgent advice for severe mood changes or exposure to chickenpox, shingles or measles. Avoid an unplanned abrupt withdrawal, especially with prior courses or doses above 40 mg.
08ComplicationsImportant consequences, why they occur and why they matter clinically.
Persistent unilateral or bilateral impairment
Incomplete recovery can affect localisation, speech in noise and awareness of sounds on the poorer side. Audiological rehabilitation should be offered according to the residual loss and practical listening needs.
Tinnitus and psychological distress
An abrupt loss can produce intrusive tinnitus, anxiety and disruption of work or relationships. Follow-up should ask about distress and provide accessible explanations, support and referral when symptoms remain troublesome.
Treatment-related harm
Systemic steroids can aggravate glucose control, blood pressure, infection risk and psychiatric symptoms. Intratympanic treatment has different local risks, including discomfort, transient dizziness, infection and persistent membrane perforation.
09Monitoring and follow-upTreatment response, safety checks and longer-term review.
- Arrange repeat audiometry and compare the actual thresholds with baseline, rather than judging recovery solely from reduced fullness or tinnitus.
- Review glucose, blood pressure and other treatment risks according to baseline disease, dose and symptoms; provide a route for urgent steroid adverse-effect advice.
- Check completion and interpretation of planned MRI or directed investigations, even if some hearing has improved.
- Ask about tinnitus, sleep, anxiety, work and communication needs, and arrange hearing support if the deficit remains functionally important.
- Confirm that the patient understands the precise reduction and stop dates and that a pre-existing steroid regimen has been reconciled.
10Special situationsVariants, exceptions and circumstances that change the usual approach.
The referral rule does not depend on a measured 30 dB loss
A person without an immediate audiogram cannot demonstrate a formal numerical decline at presentation. NICE's urgent referral recommendation is based on the sudden clinical history and absence of an adequate external or middle-ear explanation. Do not convert a research definition into a gate that delays access to care.
Use the national referral categories explicitly
Some local summaries compress rapid and sudden hearing-loss wording. The NICE distinction remains important: recent sudden loss requires assessment within 24 hours, while sudden loss older than 30 days or worsening over four to 90 days generally needs assessment within two weeks. Additional emergency findings can require faster action.
Intratympanic treatment needs a procedural plan
The ENT team selects the agent, concentration, injection schedule and local precautions. Its consideration can be valuable when systemic treatment is unsuitable or recovery is limited, but it should not be presented as a universal interchangeable dose equivalent to oral prednisolone.
Avoid a guarantee of recovery
Explain that early management aims to improve the chance of benefit without promising restoration. Persistent symptoms deserve continued care, not an implication that the patient missed their only opportunity. Rehabilitation, tinnitus support and diagnostic follow-through remain useful even when the acute treatment period has passed.
11Common pitfallsFrequent interpretation and management errors.
- 01
Reassuring because the tympanic membrane looks normal despite a convincing sudden hearing change.
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Waiting for an elective audiogram or MRI before making an urgent referral.
- 03
Applying the 24-hour category to every gradual decline without distinguishing onset duration and elapsed time.
- 04
Prescribing high-dose prednisolone without documenting the taper, prior steroid exposure and major patient-specific risks.
- 05
Failing to arrange repeat hearing measurement and support after the initial medication course.