We live in a world centred on sound and sudden hearing loss is a very frightening and isolating experience that can affect work, relationships and interaction with others. Sudden hearing loss is defined as deafness that happens instantly or that develops over a few days. This may happen without warning, or follow a loud popping sound. Many people with sudden hearing loss also feel dizzy and experience tinnitus – ringing noises and other sounds.
This article on sudden hearing loss is by Kathryn Senior, a freelance journalist who writes health, medical, biological, and pharmaceutical articles for national and international journals, newsletters and web sites.
Types of sudden hearing loss
There are two main types of sudden hearing loss:
- Conductive hearing loss: this is usually due to a blockage in the ear caused by infection, inflammation or simply ear wax, or damage to the middle or inner ear, such as a burst eardrum.
- Sensorineural hearing loss: this usually results from damage to the hair cells or to the auditory nerve that interrupts transmission of sound information from the ear to the brain.
It is possible to have sudden hearing loss that is due to both causes at the same time – this is known as mixed hearing loss.
Around 85% of cases of sudden hearing loss have an unknown cause – this is known as idiopathic sudden sensorineural hearing loss or ISSHL. The remaining 15% of cases have an identifiable cause:
Blockage and sudden hearing loss
The ears naturally produce wax, which protects and lubricates the inside of the ear. A build up of wax can cause sudden conductive hearing loss, especially if you accidentally push a plug of wax into the hearing canal when cleaning the ear with cotton buds.
Drugs and sudden hearing loss
Some drugs can cause sudden deafness. This may be temporary and hearing returns to normal when the course of drugs is completed, or permanent if the drug causes sensorineural hearing loss by damaging the hair cells or auditory nerve. Drugs that induce sudden hearing loss are described as ototoxic. Ototoxic drugs are taken to prevent or treat serious disease, and include high doses of aspirin, cancer chemotherapy and radiotherapy, antimalarial drugs for treatment and prevention, aminoglycoside antibiotics, and diuretics, used in kidney and heart failure.
Injury and sudden hearing loss
Head injuries and exposure to explosions may cause sudden hearing loss, which can be temporary or permanent. Impact injuries or noise damage can cause tears in the eardrum, damage to the bones in the middle ear, or harm to the inner ear.
Infection and sudden hearing loss
Viral and bacterial infections, such as bacterial meningitis, measles, mumps, herpes zoster (shingles) can cause sudden hearing loss if they affect the inner ear, and may cause permanent sensorineural hearing loss. Vaccination can prevent many of these diseases.
There are several, more rare, instances in which hearing is lost suddenly:
Ménière's disease (an inner ear problem).
Acoustic neuromas (non-cancerous tumours on the auditory nerve) usually cause gradual hearing loss, but 10-15% of people with these diseases experience sudden hearing loss. Surgery to remove an acoustic neuroma can also cause sudden hearing loss.
Autoimmune inner ear disease (AIED) can cause sudden hearing loss.
Multiple sclerosis can affect the brainstem, causing deafness, but this often recovers spontaneously.
Many people with sudden hearing loss find that their hearing begins to return within a few days to a few weeks, but around 15% find that it does not. It is important to see a doctor as soon as possible, as starting treatment early can improve the outcome. The treatments available for sudden hearing loss include:
Steroid treatment – in ISSHL, steroids may help, perhaps by reducing swelling and inflammation.
Wax removal – wax can be removed using eardrops or by syringing using warm water, but this should only be carried out by a doctor or other health professional.
Interrupting drug treatment – if prescription drugs cause sudden hearing loss, discontinuing treatment can improve or reverse the hearing loss – however, you should only stop taking drugs or change the dose after taking advice from a doctor.
Surgery – small tears in the eardrum can repair themselves naturally but larger tears or damage to the bones in the inner ear may require surgical repair.
Treating infection – if the sudden hearing loss is caused by a bacterial or viral infection, antibiotics or antiviral drugs might relieve the symptoms, or the hearing loss may resolve spontaneously as the infection gets better.
Diet – people with Ménière's disease might find that a low salt diet helps with hearing loss and dizziness.