Sudden deafness is severe or complete hearing loss that develops over a few hours or is noticed on awakening. Such hearing loss typically affects only one ear (unless the cause is a drug). Depending on the cause of sudden deafness, people may have other symptoms such as ringing in the ears (tinnitus), dizziness, or a false sensation of spinning or moving (vertigo). About 1 in 5,000 people each year develop sudden deafness. For hearing loss that develops gradually, see Hearing Loss and Deafness: Hearing Loss.

Causes

Causes of sudden deafness fall into 3 general categories:

• An unknown cause
• An obvious explanatory event (such as a brain infection or head injury)
• An underlying disorder that has caused few or no other symptoms

Unknown cause: In most people, no cause can be found for their sudden deafness. However, doctors have several theories. Possible causes include viral infections (particularly infections with herpes simplex virus), an attack on the inner ear or its nerves by the body's immune system (autoimmune reaction), and blockage of the small blood vessels of the inner ear or the blood vessels of its nerves. Perhaps different causes affect different people.

Obvious event: In many other people, a cause for the sudden deafness is obvious. Such causes include

• Head injury
• Severe pressure change
• Drugs that damage the inner ear (ototoxic drugs)
• Infections

Head injury (such as a fracture of the temporal bone in the skull or sometimes a severe concussion without a fracture) can damage the inner ear and cause sudden hearing loss.

Severe pressure changes (such as those that can occur with diving or less often by bearing down during weightlifting) can cause a hole (fistula) to form between the middle and inner ear. Sometimes, such a fistula is present from birth and can spontaneously cause sudden hearing loss or make the person more susceptible to hearing loss after a head injury or pressure changes.

Ototoxic drugs (see Hearing Loss and Deafness: Some Causes and Features of Hearing Loss) are drugs that have damaging side effects to the ears. Some drugs can rapidly cause hearing loss, sometimes within a day (especially with an overdose). A few people have a rare genetic disorder that makes them more susceptible to hearing loss from the class of antibiotics called aminoglycosides.

A number of infections cause sudden deafness during or immediately after acute illness. Common infections include bacterial meningitis, Lyme disease, and many viral infections. The most common viral causes in the developed world are mumps and herpes simplex brain infection. Measles is a very rare cause because most people are immunized against the infection.

Underlying disorders: Sudden deafness rarely can be the first symptom of some disorders that usually have other initial symptoms. Such disorders include a tumor of the of the auditory nerve called acoustic neuroma, multiple sclerosis, Meniere disease, or a small stroke of the balance center of the brain (the cerebellum). Sometimes a syphilis infection reactivates in people who have HIV infection. This reactivation can cause sudden deafness.

Rarer disorders include Cogan syndrome, in which an autoimmune reaction attacks the inner ear (and also the surface of the eye); certain disorders involving blood vessel inflammation (vasculitis); and blood disorders such as Waldenström macroglobulinemia, sickle cell disease, and some forms of leukemia.

Evaluation

The following information can help people decide when a doctor's evaluation is needed and help them know what to expect during the evaluation.

Warning signs: In people with sudden deafness, certain symptoms and characteristics are cause for concern. They include

• Any abnormalities of the nervous system (other than hearing loss)

When to see a doctor: Anyone with sudden deafness should see a doctor right away because some causes must be treated quickly.

What the doctor does: Doctors first ask questions about the person's symptoms and medical history. Doctors then do a physical examination. What they find during the history and physical examination may suggest a cause of the sudden deafness and the tests that may need to be done (see Hearing Loss and Deafness: Some Causes and Features of Sudden Deafness).

Doctors note whether hearing loss affects one or both ears and whether a specific event such as head injury, diving injury, or infectious illness occurred. They ask about accompanying symptoms that involve the ear (such as ringing in the ears or ear discharge), balance center (such as disorientation in the dark or vertigo), and other parts of the brain and nervous system (such as headache, weakness, or an abnormal sense of taste). They try to identify whether people are currently taking (or recently took) any ototoxic drugs.

The physical examination focuses on the ears and hearing and on examination of the nervous system.

PrintOpen table in new window
Some Causes and Features of Sudden Deafness Cause Common Features* Tests† Unknown — Deafness in only one ear No other symptoms MRI using a contrast agent (gadolinium) Obvious causes Acute infection (such as bacterial meningitis, Lyme disease, mumps, or herpes simplex) Deafness in one or both ears In people with a serious, acute illness Often headache and confusion With Lyme disease, deafness preceded by a typical rash and flu-like symptoms With mumps, pain in cheeks with swallowing A doctor's examination If not already done, blood tests and a spinal tap (lumbar puncture) Head injury Deafness in only one ear Sometimes fluid (bloody, blood-tinged, or clear) coming from affected ear CT or MRI Pressure changes (as may occur during diving) Deafness in only one ear Sudden onset during causative activity Sometimes accompanied by an explosive sound, dizziness, or ringing in the ear Tympanometry (placement of a device in the ear to measure of how well sound passes through the ear) Electronystagmography (a test to record involuntary movements of the eye caused by a condition known as nystagmus) CT Drugs that can damage the ear (ototoxic drugs) including Aminoglycosides (such as gentamicin or tobramycinSome Trade Names TOBREX ) CisplatinSome Trade Names PLATINOL Ethacrynic acidSome Trade Names EDECRIN FurosemideSome Trade Names LASIX VancomycinSome Trade Names VANCOCIN Deafness in both ears Sometimes dizziness and loss of balance In people who recently started taking an ototoxic drug A doctor's examination Hidden disorders‡ Acoustic neuroma (a tumor of the auditory nerve) Deafness in only one ear Often dizziness or a false sensation of spinning or moving (vertigo) and loss of balance Sometimes drooping facial muscles and/or numbness of the face and taste abnormalities MRI using a contrast agent (gadolinium) Autoimmune disorders, such as Cogan syndrome, some blood disorders, and disorders that cause vasculitis Deafness in one or both ears Sometimes joint pains or a rash Blood tests Meniere syndrome Deafness in only one ear in about three fourths of people Sometimes dizziness and/or ringing in the ear A doctor's examination MRI using a contrast agent (gadolinium) Multiple sclerosis Deafness in only one ear Sometimes weakness or numbness that comes and goes and that occurs in different parts of the body MRI using a contrast agent Sometimes a spinal tap Stroke (affecting the cerebellum) Deafness in only one ear Sometimes difficulty with balance or coordination MRI using a contrast agent Reactivation of syphilis in people with HIV infection Deafness in one or both ears Sometimes risk factors for sexually transmitted diseases (such as unprotected sex, multiple partners) Blood tests *Features include symptoms and the results of the doctor's examination. Features mentioned are typical but not always present. Features overlap between causes. †All people should have an audiogram. ‡Rarely, sudden deafness is the first symptom of a disorder that usually has other symptoms first. Symptoms typical of these disorders may not be present at all. However, some people disregard mild symptoms that may be discovered by the doctor through careful questioning and examination. §Mixed conductive and sensorineural loss may also be present CT = computed tomography; MRI = magnetic resonance imaging. Some Causes and Features of Sudden Deafness Cause Common Features* Tests† Unknown — Deafness in only one ear No other symptoms MRI using a contrast agent (gadolinium) Obvious causes Acute infection (such as bacterial meningitis, Lyme disease, mumps, or herpes simplex) Deafness in one or both ears In people with a serious, acute illness Often headache and confusion With Lyme disease, deafness preceded by a typical rash and flu-like symptoms With mumps, pain in cheeks with swallowing A doctor's examination If not already done, blood tests and a spinal tap (lumbar puncture) Head injury Deafness in only one ear Sometimes fluid (bloody, blood-tinged, or clear) coming from affected ear CT or MRI Pressure changes (as may occur during diving) Deafness in only one ear Sudden onset during causative activity Sometimes accompanied by an explosive sound, dizziness, or ringing in the ear Tympanometry (placement of a device in the ear to measure of how well sound passes through the ear) Electronystagmography (a test to record involuntary movements of the eye caused by a condition known as nystagmus) CT Drugs that can damage the ear (ototoxic drugs) including Aminoglycosides (such as gentamicin or tobramycinSome Trade Names TOBREX ) CisplatinSome Trade Names PLATINOL Ethacrynic acidSome Trade Names EDECRIN FurosemideSome Trade Names LASIX VancomycinSome Trade Names VANCOCIN Deafness in both ears Sometimes dizziness and loss of balance In people who recently started taking an ototoxic drug A doctor's examination Hidden disorders‡ Acoustic neuroma (a tumor of the auditory nerve) Deafness in only one ear Often dizziness or a false sensation of spinning or moving (vertigo) and loss of balance Sometimes drooping facial muscles and/or numbness of the face and taste abnormalities MRI using a contrast agent (gadolinium) Autoimmune disorders, such as Cogan syndrome, some blood disorders, and disorders that cause vasculitis Deafness in one or both ears Sometimes joint pains or a rash Blood tests Meniere syndrome Deafness in only one ear in about three fourths of people Sometimes dizziness and/or ringing in the ear A doctor's examination MRI using a contrast agent (gadolinium) Multiple sclerosis Deafness in only one ear Sometimes weakness or numbness that comes and goes and that occurs in different parts of the body MRI using a contrast agent Sometimes a spinal tap Stroke (affecting the cerebellum) Deafness in only one ear Sometimes difficulty with balance or coordination MRI using a contrast agent Reactivation of syphilis in people with HIV infection Deafness in one or both ears Sometimes risk factors for sexually transmitted diseases (such as unprotected sex, multiple partners) Blood tests *Features include symptoms and the results of the doctor's examination. Features mentioned are typical but not always present. Features overlap between causes. †All people should have an audiogram. ‡Rarely, sudden deafness is the first symptom of a disorder that usually has other symptoms first. Symptoms typical of these disorders may not be present at all. However, some people disregard mild symptoms that may be discovered by the doctor through careful questioning and examination. §Mixed conductive and sensorineural loss may also be present CT = computed tomography; MRI = magnetic resonance imaging.

Testing: Typically, people should have an audiogram (a hearing test―see Hearing Loss and Deafness: Testing). Unless doctors think the problem is clearly an acute infection or drug toxicity, they usually also do gadolinium-enhanced magnetic resonance imaging (MRI), particularly when the hearing loss is greater in one ear. Other tests are done based on the likely cause (see Hearing Loss and Deafness: Some Causes and Features of Sudden Deafness). For example, people who had a head injury should have MRI. People at risk of sexually transmitted diseases should have blood tests for HIV infection and syphilis.

Treatment

Treatment is directed at the disorder causing the sudden deafness when it is known. When the cause is unknown, many doctors try giving corticosteroids along with antiviral drugs effective against herpes simplex (such as valacyclovirSome Trade Names
VALTREX
or famciclovirSome Trade Names
FAMVIR
).

When the cause is a viral infection or is unknown, about half of people regain normal hearing and the other half recover partial hearing. Improvement, if it can be achieved, usually occurs within 10 to 14 days. Recovery from an ototoxic drug varies greatly depending on the drug and the dosage. With some drugs (such as aspirinSome Trade Names
BAYER
and diuretics), hearing returns within 24 hours. However, antibiotic and chemotherapy drugs often cause permanent hearing loss if safe dosages have been exceeded.

Key Points

• Why sudden deafness occurs is usually unknown.
• A few people have an obvious cause (such as severe head injury or infection or use of drugs that can damage hearing).
• In a very few people, sudden deafness is the first sign of an underlying disorder.

Last full review/revision December 2012 by John K. Niparko, MD