Sudden hearing loss: when it's a medical emergency.

What sudden hearing loss actually is

Sudden sensorineural hearing loss (SSNHL) is defined as hearing loss of at least 30 dB across three contiguous audiometric frequencies, developing over 72 hours or less, with sensorineural (not conductive) origin. It typically affects one ear — sudden bilateral loss is rare and triggers a different workup.

Estimates of incidence range from 5 to 27 per 100,000 people per year, with approximately 66,000 new cases annually in the United States (Chandrasekhar et al., 2019). Over 90% of cases are idiopathic — no identified cause despite workup. This is sometimes called idiopathic SSNHL (iSSNHL).

Associated symptoms commonly include tinnitus (often in the affected ear), a feeling of ear fullness, and sometimes vertigo. The presence of vertigo is associated with a worse prognosis.

The first thing the guideline emphasises: distinguish sensorineural from conductive

The 2019 AAO-HNS guideline opens with the most important diagnostic point: when a patient first presents with sudden hearing loss, clinicians should distinguish sensorineural from conductive hearing loss. This is a strong recommendation (Key Action Statement 1).

The reason: a sudden conductive hearing loss — from earwax impaction, middle-ear fluid, or eardrum perforation — has a different, often immediately reversible, treatment path. A sudden sensorineural loss is the urgent one, and the two can look identical to a patient.

A simple tuning-fork test (Weber and Rinne) at the bedside can often distinguish the two, with audiometry confirming. The guideline emphasises this distinction so that someone with reversible earwax does not receive steroid therapy, and someone with SSNHL is not sent home with reassurance.

The 14-day window: audiometric confirmation

The guideline (Key Action Statement 4) recommends that clinicians obtain, or refer to a clinician who can obtain, audiometry as soon as possible — within 14 days of symptom onset — to confirm the diagnosis of SSNHL.

Practical implications:

• If your primary-care doctor cannot get you to audiometry within 14 days, push for an audiology or ENT referral.
• Some health systems run an "SSNHL hotline" or rapid-access ENT clinic for exactly this situation. Ask.
• An emergency-department audiogram is not always available, but ED clinicians can document the symptom, perform a Weber/Rinne, and arrange follow-up.

The 2-week window: corticosteroids as an option

The guideline (KAS 8) offers corticosteroids as initial therapy within 2 weeks of symptom onset. This is listed as an option, meaning the evidence supports use but does not compel it; the decision should involve shared decision-making about benefits and risks.

Two delivery routes are used:

• Oral corticosteroids (typically a tapering course of prednisone or methylprednisolone) over 10–14 days. Systemic side effects apply.
• Intratympanic corticosteroid injection (the drug injected through the eardrum into the middle ear). Side effects are largely local; an attractive option when systemic steroids are contraindicated (e.g., poorly controlled diabetes, peptic ulcer disease).

The guideline (KAS 10) recommends intratympanic steroid therapy as salvage therapy when patients have incomplete recovery from SSNHL 2 to 6 weeks after onset of symptoms.

Hyperbaric oxygen as an option

The guideline (KAS 9a and 9b) offers hyperbaric oxygen therapy combined with steroid therapy as an option within 2 weeks of onset for initial treatment (9a) or within 1 month of onset as salvage therapy (9b). Hyperbaric oxygen alone, without steroids, is not recommended; the combination is what the evidence supports.

What the guideline recommends against

The 2019 guideline issues strong recommendations against three things that are nevertheless still sometimes seen in practice:

• Routine head CT (KAS 3) in the initial evaluation of presumptive SSNHL — non-targeted head CT does not help diagnose SSNHL and exposes patients to radiation unnecessarily. (Targeted temporal-bone CT, ordered for specific reasons, is different.)
• Routine laboratory tests (KAS 5) — broad lab panels in SSNHL do not improve outcomes.
• Routine prescription of antivirals, thrombolytics, vasodilators, or vasoactive substances (KAS 11) — despite decades of plausibility-based use, the evidence does not support these for routine SSNHL.

The follow-up: MRI for retrocochlear pathology

The guideline (KAS 6) recommends evaluating SSNHL patients for retrocochlear pathology — conditions of the auditory nerve and brainstem — using MRI or auditory brainstem response testing. The most clinically significant entity in this category is vestibular schwannoma (acoustic neuroma), a benign tumour on the vestibulocochlear nerve. About 1–3% of patients with SSNHL turn out to have an acoustic neuroma, so MRI is part of the standard workup.

The guideline (KAS 12) also recommends follow-up audiometry at the conclusion of treatment and again within 6 months.

What recovery looks like

SSNHL outcomes vary widely. Three general patterns:

• Full recovery — some patients regain all or nearly all of their hearing within weeks.
• Partial recovery — some hearing returns; some residual loss remains.
• No recovery — the hearing loss persists.

Population-level estimates suggest around half of SSNHL patients have some spontaneous recovery without treatment, though "spontaneous" is hard to disentangle from the natural course because so many patients are treated. Treatment improves the odds of meaningful recovery, particularly when started early. Severity of initial loss, presence of vertigo, time-to-treatment, and age all affect prognosis.

The guideline (KAS 13) recommends that clinicians counsel patients with residual hearing loss and/or tinnitus about audiologic rehabilitation — including hearing aids and supportive measures. SSNHL with residual loss is one of the conditions for which prescription hearing aids are clearly indicated.

How to advocate for yourself in the first 72 hours

If you experience sudden hearing loss:

1. Don't wait to see if it goes away. The treatment window is short.
2. Call an ENT or audiology practice today. Ask specifically for "sudden hearing loss" or "SSNHL evaluation" — this often triggers a same-week appointment slot.
3. If you cannot reach one, contact your primary-care provider and request a referral. Mention the AAO-HNS 14-day guideline if needed.
4. If neither is available, an urgent-care or ED visit is reasonable for documentation and tuning-fork testing, even though most EDs do not have audiometry.
5. Avoid driving long distances if you have vertigo with the hearing loss.
6. Write down the timeline — when symptoms started, what changed, any associated symptoms (tinnitus, fullness, vertigo, neurological changes). This helps the clinician.

The bottom line

Sudden sensorineural hearing loss is treated as a medical priority because time-to-treatment matters. The 2019 AAO-HNS Clinical Practice Guideline lays out a clear pathway: confirm with audiometry within 14 days, consider corticosteroids within 2 weeks of onset, evaluate for retrocochlear pathology with MRI, follow up audiometrically at the end of treatment and within 6 months, and counsel about audiologic rehabilitation if hearing loss persists. If you are within the first 14 days of an episode, the most important step is finding care — not deciding which treatment is best.