Sudden hearing loss in one ear: causes, red flags and when to get it checked

Sudden hearing loss in one ear may be a simple blockage of sound reaching the inner ear or a problem in the cochlea or hearing nerve. Because distinguishing the two needs a quick examination and a hearing test, it is best done urgently rather than watched for improvement.

• Earwax blockage, which can cause what feels like sudden deafness after water exposure or ear manipulation.

• Fluid behind the eardrum or middle-ear infection, often after a cold.

• Eustachian tube dysfunction.

• Perforated eardrum after infection, barotrauma or injury.

• Idiopathic sudden sensorineural hearing loss: loss of 30 decibels or more over three adjacent frequencies within 72 hours, usually without a clear cause.

• Viral infection of the inner ear or nerve, including after mumps, shingles of the ear (Ramsay Hunt) or other viruses.

• Meniere disease, autoimmune inner-ear disease, and ototoxic medicines.

• Acoustic neuroma, stroke affecting the inner-ear circulation, and head or noise trauma.

Dizziness or spinning, facial weakness, ear pain with a blistering rash, hearing loss with a head injury or after loud explosion, sudden loss in both ears, or neurological signs warrant immediate assessment.

• Call 999: hearing loss with facial droop, slurred speech, weakness, severe headache or after a significant head injury.

• Same-day or next-day ENT, GP or urgent care: any sudden hearing loss in one ear, particularly with tinnitus or dizziness.

• Same-day GP: ear pain with a blistering rash on or around the ear, or facial weakness (Ramsay Hunt).

• GP within days: gradual muffling with a cold that is not improving.

Questions include how and when hearing dropped, associated tinnitus or vertigo, ear pain or discharge, recent illness, injury, loud noise, medicines and other conditions. The ear canal and drum are examined, tuning-fork tests (Rinne and Weber) identify the type of loss, and the face and nerves are checked.

• Pure-tone audiometry: confirms and measures the loss, and its type.

• Tympanometry: checks middle-ear function.

• MRI of the internal auditory canals: to exclude a nerve tumour or other cause, usually after treatment has begun.

• Blood tests: for diabetes, infection, autoimmune markers or clotting issues where indicated.

Do not wait to see whether it improves. Avoid loud noise, keep the ear dry if there is infection and avoid inserting anything into the ear. Treatment of sudden sensorineural loss typically involves a short course of high-dose oral steroids or steroid injection into the middle ear, as directed by an ENT specialist. Recovery varies and some hearing may not return, in which case hearing aids and tinnitus support help.

The NHS route is usually a same-day GP or urgent ENT pathway; some areas have rapid-access ENT. Private ENT and audiology can see you quickly and arrange audiometry and MRI.