Hearing Loss in One Ear – Causes & Treatments

Hearing loss does not always affect two ears; in some cases it only affects one ear. Hearing loss in one ear is known as unilateral hearing loss, the opposite of bilateral hearing loss (hearing loss in both ears).

People with unilateral hearing loss often have normal hearing in the other ear. However, even if the other ear works, hearing loss in one ear can still cause difficulties with hearing in general. For instance, people with unilateral hearing loss often have problems with localizing sound (determining where sound is coming from), focusing on sounds of interest in noisy places, hearing speech and other sounds from faraway or from another room.

Most children with hearing loss in one ear are able to develop speech and language normally without special intervention but some children may experience problems with language development such as speech delays and difficulty pronouncing certain words and sounds. Difficulties caused by hearing loss in one ear can vary from person to person.

Causes of Hearing Loss in One Ear

Unilateral hearing loss is caused by a number of different factors. Some causes may be easy to determine whereas others may be difficult to detect. Some of the most common causes of hearing loss in one ear include:

  • Genetics

Hearing loss can be genetic.  To determine whether unilateral hearing loss is inherited, it is best to seek professional help from a geneticist. Gene testing is recommended for people with hearing loss in the family to determine the risk factors of passing it on during pregnancy.

  • Problems with the Middle Ear

This is a common cause of unilateral hearing loss in children. Common problems with the middle ear that may cause hearing loss include: otitis media (inflammation of the middle ear), earwax buildup, fluid buildup, and middle ear infections.

  • Aging
  • Prolonged or constant exposure to loud noises that are 85 decibels and above
  • Head injury or ear injury
  • Illnesses (e.g. measles, meningitis, HIV/AIDS, meniere’s disease, and mumps)
  • Ototoxic Medication (aspirin, loop diuretics, chemotherapy drugs, antibiotics).
  • Congenital causes

The state of the mother during pregnancy can have a direct effect on the child’s hearing. Congenital causes of hearing, loss in one ear may include: illness or infection during pregnancy, drug/alcohol intake, premature birth, and birth asphyxia.

Treatments of Unilateral Hearing Loss

The treatment for hearing loss in one ear will highly depend on the causes, type, and degree of hearing loss

Majority of hearing loss cases is sensorineural, a type of hearing loss that affects the hair cells in the cochlea. In most cases, sensorineural hearing loss is irreversible and as such, it cannot be treated with surgery or medication. It can, however, be managed with hearing aids, cochlear implants, and other assistive listening devices.

For sensorineural unilateral hearing loss caused by a virus, medication may work for treatment but it is not always guaranteed to be effective.

Conductive unilateral hearing loss, on the other hand, can be surgically corrected depending on the underlying problem. Since conductive hearing loss is typically caused by malformation of the ear canal and problems with the internal structure of the middle ear, surgery may be able to correct these problems.

If it is caused by fluid buildup infections, antibiotics are typically administered to treat the infection.


In cases where restoration of hearing is not possible, there are ways to manage unilateral hearing loss. One common method is through the use of Contralateral Routing of Offside Signals hearing aids (CROS).

CROS hearing aids are designed specifically to manage unilateral hearing loss. It works by transferring sounds from the damaged ear to the hearing ear to help with a person’s overall hearing.

CROS hearing aids come in various types. The most common type has two units that are connected either through wires or wirelessly. They work by transferring sounds from one ear to another.

Regular hearing aids can also be used for the management of unilateral hearing loss by amplifying sound for the hearing-impaired ear.

The method of management depends significantly on the personal circumstances of the person with unilateral hearing loss. It is best to work with an audiologist to find the most suitable treatment option for your particular type and degree of hearing loss.

Common Causes of Hearing Loss

Hearing loss affects about 48 million people in the US and 360 million people worldwide, making it one of the most common health conditions in the world.

There are many factors that cause hearing loss. Some causes are genetic and some are environmental. While some causes of hearing loss can be avoided with safety precautions, others, unfortunately, are unavoidable.

Below are some of the most common causes of hearing loss in both children and adults:

Hereditary Causes

Hereditary hearing loss is inherited from the parents. Depending on the factors involved, the hearing loss can be sensorineural, conductive, or mixed. Some hereditary causes are syndromic, meaning the hearing loss is caused by an underlying hereditary health condition (such as illness or malfunctions in the outer ear).

Some cases of hearing loss are inherited through genes. Genetic risk factors can often be determined with gene testing.

Ototoxic Medication

Certain drugs can be ototoxic (damaging to the ear) when taken for a prolonged period or when taken in large doses. Some ototoxic drugs include, antibiotics, loop diuretics, aspirin (in large doses), and some chemotherapy drugs (including carboplatin and cisplatin, among others),


Certain illnesses can cause hearing loss as a side effect. Some illnesses known to cause hearing loss include: meningitis, measles, mumps, otosclerosis (a disease of the middle ear), HIV/AIDS, and presbycusis, among others.

Meniere’s disease is also known to cause hearing loss in adults. The disease affects the inner ear and common symptoms include tinnitus, vertigo, and sensorineural hearing loss.  Hearing loss caused by the disease can vary from mild to severe.

Exposure to Loud Noise

Noise-induced hearing loss is very common in adults but can also affect children. In fact, about 12.5% of children in the US (ages 6 to 19 years old) have some degree of noise-induced hearing loss. Prolonged exposure to loud sounds above 85 decibels can cause permanent hearing loss.

In some cases, a one-time exposure to a very loud noise (such as an explosion) can cause sudden hearing loss that may either be temporary or permanent.


Hearing loss is a common side effect of aging. As we age, a number of hair cells in the inner ear deteriorate and lose their function. 1 in 3 people aged 65 and above develop hearing loss.

Otits Media

Otitis media or inflammation of the middle ear is a common cause of hearing loss in children because the Eustachian tube (the tube that connects the middle ear to the nasopharynx at the back of the throat) is not yet fully developed and is susceptible to fluid buildup. The condition itself is typically caused by ear infections and fluid buildup.

Congenital Causes

Congenital hearing loss (present at birth or shortly after birth) can be hereditary or non-hereditary.  It can also be caused by problems during pregnancy. Common causes of hearing loss that are not hereditary include: developing infections during pregnancy (e.g. syphilis, rubella), alcohol and drug use, lack of oxygen at birth (birth asphyxia), and premature birth.

Other Common Causes

Other causes of hearing loss not classified above include: chronic ear infections, head injuries or ear injury (caused by impact), and earwax buildup.