Sudden hearing loss in one ear

If you or a loved one has suddenly developed hearing loss, see your doctor right away. While often downplayed as not serious, any new or sudden hearing loss should be taken seriously by you and your healthcare providers. Why? The sooner you get a thorough audiological workup, the better your chances are for a full recovery.

Sudden hearing loss usually only affects one ear, and for those who don't get better, permanent single-sided deafness can be the outcome. This kind of hearing loss, also known as unilateral hearing loss, presents unique problems, such as the inability to know where sounds are coming from, and something known as the "head shadow" effect. In some cases, a person will still have some hearing ability left, which can be amplified with a hearing aid.

What is sudden hearing loss?

Also known as sudden sensorineural hearing loss, or SSNHL, sudden-onset hearing loss occurs all at once or over the course of several days. About one out of every 5,000 adults experiences sudden-onset hearing loss annually, though that number could be much higher due to the number of cases that go unreported and undiagnosed.

Men and women are affected equally, and the average age of first occurrence is typically mid-40s to mid-50s. 

For most people, the immediate assumption is that they are suffering from allergies, an earwax blockage or sinus infection, so they might decide not to seek treatment—but prompt treatment is vital. 

I suddenly can't hear well out of one ear. What should I do?

Sudden-onset hearing loss is considered a medical emergency, and prompt treatment might just save your hearing.

Symptoms of sudden hearing loss

Some people notice sudden hearing loss when they wake up first thing in the morning and realize their hearing is different. Others don’t notice a difference until they hold the phone up to the affected ear or try to listen to headphones. In some cases SSNHL is preceded by a very noticeable “pop," which can be quite alarming.

Afterward, some patients report a feeling of fullness in the affected ear or a strange feeling on that side of the head, possibly accompanied by sudden ringing in the ear (tinnitus) and dizziness. This is sometimes called "aural fullness."

The cause of sudden hearing loss is often unknown

SSNHL differs from other types of hearing loss in a couple of important ways. Aside from its rapid onset, it is often idiopathic, meaning the cause is usually unknown. A cause can be identified in only 10 to 15 percent of diagnosed cases.

Some possible known risk factors and causes include:

• Bacterial infection 
• Viral infection
• Inner ear disorders, especially Meniere's disease
• Migraines
• Tumors (e.g. acoustic neuroma)
• Some drugs can cause hearing loss as a side effect, known as ototoxic medications, especially if taken in high doses
• Neurologic diseases or disorders (e.g. multiple sclerosis)
• Head injury or trauma
• Autoimmune inner ear disorder and other autoimmune diseases
• Low thyroid hormones, such as from autoimmune hypothyroidism
• Circulation issues (e.g. vasculitis)

Did a virus cause my sudden hearing loss?

Researchers think that in cases of sudden hearing loss where no obvious cause can be identified, a mild viral infection may have been to blame. This is because people often report having a head cold or respiratory infection in the days and weeks before they lost their hearing.

How would it do this? The virus itself—or the resulting inflammation—somehow damages the inner ear's delicate hair cells and/or the blood supply. Any number of viruses may be responsible, including some that may not produce many symptoms, meaning a person is unaware they're sick until they experience hearing loss. This is an area of emerging research.

COVID-19 and sudden hearing loss

Given that viral infections are thought to be one of the most common causes of sudden hearing loss, is the same true for COVID-19, the novel coronavirus that triggered a pandemic? 

It appears that in rare cases, yes, it can lead to hearing loss. However, researchers' understanding of this relationship is new. (We're updating this article on COVID-19 and hearing loss each time we find out about a new study on the topic.)

What about the vaccines?

So far, data from the CDC's Vaccine Adverse Events Reporting System does not indicate any link between vaccination and sudden hearing loss. The rate of sudden hearing loss appears to actually be lower among vaccinated people, though researchers from Johns Hopkins School of Medicine say cases could be under-reported. Their results were published in May 2021 in a research letter in the medical journal JAMA Otolaryngology–Head and Neck Surgery.

Other viruses 

Quite a few viruses, some of them life-threatening, can cause hearing loss, either gradual or sudden. Many of them are vaccine-preventable, such as measles, mumps and rubella, and chickenpox (varicella). Because these often produce widepsread severe symptoms, these cases are easier to catch and treat earlier.

Testing for sudden hearing loss

If you suspect you might have SSNHL, the first step is to make an appointment with a hearing healthcare professional. She may conduct a hearing test called pure tone audiometry to measure the hearing loss. 

The test can also determine the range of hearing loss in decibels. SSNHL will be diagnosed in the case of a hearing loss of at least 30 decibels in at least three connected frequencies. After diagnosis, she may order further tests in an attempt to determine an underlying cause. Blood tests, MRIs and balance tests are just a few examples that might help get to the bottom of your hearing loss.

If any of your healthcare providers are unwilling to thoroughly investigate your sudden hearing loss, seek a second opinion. As audiologist Dennis Colucci stated, healthcare providers must "understand that sudden hearing loss is a medical emergency. Without immediate action, there is likely to be less benefit and more burden to patients, their families, and the healthcare system."

Treating sudden hearing loss: Can you get your hearing back?

Although treatments for sudden hearing loss are still fairly limited, they are important: 85% of those who receive prompt medical attention regain some or all of their hearing. This is mostly good news for people hoping to regain their hearing in one ear.

The drugs used to to treat sudden hearing loss are steroids, which suppress inflammation. Specifically, corticosteroids are the most common treatment for SSNHL. They work by helping the body fight illness, decreasing swelling and reducing inflammation. Usually administered in pill form, the steroids also can be given through an injection behind the eardrum.

With prompt treatment, you have a good chance of regaining some or all of your lost hearing.

Steroid therapy for SSNHL

This treatment via injection, called intratympanic corticosteroid therapy, is recommended for those who are unable to take oral steroids. Both treatments are equally effective, although the injections are known to be somewhat uncomfortable. Additional treatments may be necessary to treat the underlying cause, for example, taking antibiotics for an infection.

About 50 percent of people who experience SSNHL will spontaneously recover all or some of their hearing within one to two weeks. Still, it is vital to seek treatment as soon as possible, as the window to restore hearing closes about two to four weeks after the onset of the hearing loss. After that, the hearing loss will likely become permanent and irreversible.

After that, treatments will focus on amplifying any remaining sound a person has, via hearing aids or similar devices. 

The window to restore hearing closes two to four weeks after the onset of the hearing loss, meaning the hearing loss will then become permanent and irreversible.

If you experience sudden onset hearing loss, don’t ignore it in the hopes that it will go away. Seeking treatment from a hearing professional immediately could make all the difference.