You can go deaf from loud noise, aging, infections, genetics, medications, head injuries, or a combination of these factors. Over 430 million people worldwide currently have disabling hearing loss, and the World Health Organization projects that number will exceed 700 million by 2050. Some causes are preventable, others aren’t, but understanding them helps you protect the hearing you have.
Two Types of Hearing Loss
How you go deaf depends on which part of your ear is affected. There are two main categories, and they work very differently.
Sensorineural hearing loss comes from damage inside the inner ear or to the nerve that carries sound signals to your brain. The inner ear contains thousands of microscopic hair cells that vibrate in response to sound waves. When those cells are destroyed by noise, disease, or aging, they don’t grow back. This is the most common and usually permanent type of hearing loss.
Conductive hearing loss happens when something physically blocks sound from reaching the inner ear. A buildup of earwax, fluid from an ear infection, a ruptured eardrum, or abnormal bone growth in the middle ear can all cause this. Because the inner ear itself is still healthy, conductive hearing loss is often treatable or reversible once the blockage is removed.
Some people develop both types at the same time, which is called mixed hearing loss.
Loud Noise Exposure
Noise is one of the most common preventable causes of permanent deafness. Sounds at or below 70 decibels, roughly the volume of a washing machine, are unlikely to cause hearing loss no matter how long you’re exposed. But repeated or prolonged exposure at 85 decibels or above starts destroying those irreplaceable hair cells in the inner ear.
The louder the sound, the faster the damage happens. The National Institute for Occupational Safety and Health sets the workplace limit at 85 decibels for an eight-hour shift, and for every 3-decibel increase above that, the safe exposure time drops by half. At 88 decibels, you have four hours. At 91, two hours. A rock concert at 110 decibels can cause permanent damage in under two minutes.
Noise-induced hearing loss can also happen in a single moment. A gunshot, explosion, or industrial accident can destroy hearing instantly. This type of damage is permanent because the hair cells in your inner ear, once killed, never regenerate.
Aging
Age-related hearing loss, known clinically as presbycusis, is the single most common cause of deafness in adults. It typically begins gradually after age 60, though it can start earlier. The primary cause is the slow, cumulative loss of sensory hair cells in the inner ear. Changes can also occur in the middle ear structures and along the nerve pathways that transmit sound to the brain.
Because this process is gradual, many people don’t notice it at first. High-frequency sounds, like the voices of children or consonant sounds in speech, tend to fade first. Over years or decades, the loss can progress to the point where normal conversation becomes difficult to follow without hearing aids.
Infections and Illness
A surprising number of infections can cause partial or total deafness, sometimes permanently.
Bacterial meningitis is one of the leading causes of acquired deafness. Roughly 8% of survivors experience some degree of permanent hearing loss. The bacteria most commonly responsible are the same ones that cause pneumococcal disease and meningococcal meningitis.
Several viral infections also pose serious risks. Measles was responsible for 5% to 10% of profound hearing loss cases in the United States before widespread vaccination. Mumps is one of the most common causes of sudden, permanent hearing loss in one ear. Rubella contracted during pregnancy can cause congenital rubella syndrome in the baby, and hearing loss from this condition is permanent. Cytomegalovirus (CMV), a common virus that most people contract without knowing it, is the leading non-genetic cause of hearing loss in newborns in developed countries.
More recently, COVID-19 has been linked to hearing and balance problems. A 2022 meta-analysis of 26 studies found tinnitus in about 8% of COVID cases and dizziness in nearly 18%. The virus can damage both the cochlea and auditory processing areas of the brain.
Syphilis, if untreated, can damage the auditory nerve and cause irreversible hearing loss. HIV can affect hearing through multiple pathways: direct damage to inner ear structures, nerve damage, opportunistic infections, and even the medications used to treat it.
Medications and Chemical Exposure
Certain medications are “ototoxic,” meaning they can poison the delicate sensory cells in your inner ear. The risk is real enough that doctors monitor hearing during treatment with some of these drugs.
Chemotherapy drugs, particularly those containing platinum compounds, are among the most damaging to hearing. Some patients experience permanent hearing loss as a side effect of cancer treatment. Certain powerful diuretics used to treat fluid retention and heart failure can also cause hearing damage, particularly at high doses or when combined with other ototoxic drugs.
Even common over-the-counter medications carry some risk. Aspirin, taken in high doses over a long period, can cause temporary hearing loss or ringing in the ears. Antimalarial drugs containing quinine have similar effects. Environmental chemicals including mercury, lead, tin, and carbon monoxide can also damage hearing with chronic exposure.
Genetics
About half of childhood deafness has a genetic origin. Researchers have identified more than 155 genes that, when altered, can cause hearing loss on their own, without any other symptoms or health conditions.
The most common genetic culprit is a gene called GJB2, which is responsible for roughly half of all cases of inherited nonsyndromic hearing loss (hearing loss that occurs without other medical problems). This gene helps produce a protein essential for the function of cells in the inner ear. When it’s altered, the inner ear can’t process sound properly from birth.
Genetic hearing loss can be inherited in several patterns. Some forms require both parents to carry the gene variant, meaning neither parent is deaf themselves. Other forms need only one copy of the altered gene, so a deaf parent has a 50% chance of passing it on. In rarer cases, the gene is carried on the X chromosome, primarily affecting boys.
Head Trauma
A severe blow to the head can cause immediate hearing loss. The temporal bone, which houses the structures of the ear, sits on either side of the skull and is vulnerable to fracture during car accidents, falls, assaults, or sports injuries.
Most temporal bone fractures (about 90%) spare the bony shell around the inner ear, and hearing loss from these injuries often improves on its own. But when the fracture cuts through the cochlea or the bony canals of the inner ear, the rate of permanent sensorineural hearing loss jumps to between 40% and 100%. Fractures can also dislocate or damage the tiny chain of bones in the middle ear, causing conductive hearing loss that may require surgical repair if it doesn’t resolve.
Sudden Hearing Loss
Some people lose hearing in one ear over hours or days with no obvious cause. This is a medical emergency. Sudden sensorineural hearing loss affects the inner ear or auditory nerve, and the treatment window is narrow. Starting steroids quickly improves the odds of recovery, but delays reduce the chance that hearing will return. If you wake up one morning and can’t hear out of one ear, or notice a dramatic drop in hearing alongside ringing or dizziness, getting evaluated the same day matters.
How to Protect Your Hearing
Not all causes of deafness are preventable, but the biggest controllable risk factor is noise. Wearing earplugs or noise-canceling headphones in loud environments, keeping personal audio devices below 70 decibels, and limiting time spent at high-volume events are the most effective steps you can take. Workplace noise protection is especially important for people in construction, manufacturing, music, and military settings.
Vaccination prevents several infections that cause deafness, including measles, mumps, rubella, and bacterial meningitis. If you’re prescribed a medication known to affect hearing, ask about monitoring and whether alternatives exist. And if you notice any sudden change in hearing, treat it as urgent rather than waiting to see if it resolves on its own.