A reduction in hearing in one ear, known as unilateral hearing loss, can affect individuals of all ages. While often minor and temporary, it can signal a more serious underlying health concern. Understanding its causes is important.
Common Reasons for Reduced Hearing in One Ear
A common cause of reduced hearing in one ear is earwax accumulation. Excessive buildup can block the ear canal, preventing sound waves from reaching the eardrum. This often leads to muffled hearing, which resolves with professional removal.
Ear infections, affecting the outer or middle ear, are another common cause. Outer ear infections (otitis externa or “swimmer’s ear”) cause inflammation and swelling, obstructing sound. Middle ear infections (otitis media) involve fluid buildup behind the eardrum, hindering its vibration and causing muffled hearing. A foreign object lodged in a child’s ear canal can also block sound.
Eustachian tube dysfunction can also cause one-sided hearing changes. Often caused by colds, allergies, or sinus infections, this dysfunction prevents proper air pressure equalization in the middle ear. This imbalance can cause a feeling of pressure, popping, and muffled hearing. A perforated eardrum (a tear in the tympanic membrane) directly impairs its vibration, leading to hearing loss. Such perforations can result from severe infections, sudden loud noises, or trauma to the ear.
Inner Ear and Nerve-Related Causes
One-sided hearing loss can also stem from complex issues within the inner ear or involving the auditory nerve. Sudden sensorineural hearing loss (SSNHL) is a medical emergency: a rapid, unexplained loss of hearing, usually in one ear, occurring instantly or over days. Its exact cause is often unknown, but it can be linked to viral infections, circulatory problems, or autoimmune diseases. SSNHL involves damage to the inner ear’s sensory organs (cochlea) or nerve pathways to the brain.
Meniere’s disease is a chronic inner ear disorder caused by excess endolymph fluid. This fluid imbalance causes fluctuating hearing loss (often in one ear and lower frequencies), severe vertigo, ringing (tinnitus), and ear pressure. Symptoms occur in unpredictable attacks lasting minutes to hours.
An acoustic neuroma (vestibular schwannoma) is a benign tumor on the vestibular nerve, connecting the inner ear to the brain. This slow-growing tumor can press on hearing and balance nerves, causing gradual, one-sided hearing loss, tinnitus, and balance issues. Though rare, it is a significant cause of progressive unilateral hearing loss.
Loud noise exposure can damage inner ear hair cells, leading to noise-induced hearing loss. This damage may be more pronounced in one ear, especially with uneven exposure. Otosclerosis involves abnormal bone growth in the middle ear, often around the stapes bone. This growth hinders the stapes from vibrating, impeding sound transmission and causing gradual conductive hearing loss, which can affect one or both ears.
When to Seek Professional Medical Advice
Consult a healthcare provider for any hearing changes, especially if it affects only one ear. Prompt attention is important if hearing loss occurs suddenly (over hours or days). This could indicate sudden sensorineural hearing loss, which benefits from early treatment.
Seek a doctor’s visit if hearing loss is accompanied by ear pain, discharge, or fever. A medical evaluation is also recommended if hearing loss comes with dizziness, vertigo, or persistent ringing (tinnitus). These additional symptoms can point towards more serious underlying conditions. Even gradual hearing loss or loss without an apparent cause warrants professional advice.
What to Expect at the Doctor’s Visit and Potential Treatments
A doctor’s visit for one-sided hearing loss begins with a review of your symptoms and medical history. The doctor will examine your ear with an otoscope to inspect the ear canal and eardrum for blockages, infection signs, or a perforated eardrum. This initial inspection helps rule out common, easily treatable causes.
After the visual exam, a comprehensive hearing test (audiometry) will likely be performed by an audiologist or doctor. This test measures hearing ability across frequencies and volumes, determining the type and degree of loss and identifying the affected ear part. If a complex cause like a tumor is suspected, imaging tests (MRI or CT scan) may be ordered for detailed inner ear images.
Treatment varies depending on the cause. Earwax buildup can be easily removed in the doctor’s office. Bacterial ear infections are treated with antibiotics; sudden sensorineural hearing loss may involve corticosteroids.
Minor procedures like ear tubes for chronic fluid buildup or perforated eardrum repair might be considered. Surgery may be necessary for conditions like otosclerosis (stapedectomy to replace the middle ear bone) or to remove an acoustic neuroma. If hearing loss is irreversible, hearing aids or cochlear implants can amplify sound or stimulate the auditory nerve.