Not long ago, I lost my hearing…again. As usual, I first blamed my phone for the muffled voices on the other end. Then, the loud, high-pitched ringing in my ears started, making everything even harder to hear. Finally, when I couldn't hear the TV on maximum volume, I was forced to turn on captions.

After a week of hoping it would clear up on its own, my hearing problem became intolerable, and I finally made a doctor’s appointment. It took ten minutes for the ENT to vacuum out the impacted earwax blocking my eardrum, and my hearing immediately returned to normal. If I sound familiar with this routine, it’s because I’ve been through it several times. I have an underactive thyroid, hypothyroidism, which makes me more likely to develop earwax problems.

The thyroid is a small, butterfly-shaped gland located in the neck that controls energy and metabolism. My hypothyroidism is caused by Hashimoto's disease, a common autoimmune condition. Hashimoto's and hypothyroidism affect an estimated 15 to 20 million Americans. But many of those patients–and even some health care providers–aren’t aware of the connection between thyroid conditions and hearing loss. So, let's take a look at this critical and often overlooked link.

About hearing loss

Hearing loss falls into three primary categories: 

• Sensorineural hearing loss stems from problems in the inner ear or the auditory nerve. It’s the most common type of hearing loss, making up around 90 percent of all hearing issues, including in Hashimoto’s and hypothyroidism patients.
• Conductive hearing loss, typically due to a blockage or injury, prevents sound from reaching the inner ear. (My impacted earwax, for example, resulted in conductive hearing loss.)
• Mixed hearing loss is a combination of sensorineural and conductive hearing loss.

The symptoms of hearing loss can vary and include:

• Tinnitus, a ringing, buzzing, hissing, or roaring sound in your ears that may be continuous or intermittent.
• A feeling of pressure or fullness in and around the ears.
• A need to increase the volume of your television, radio, telephone, and electronic devices in order to hear them.
• Other people’s speech sounds slurred, mumbled, and hard to understand, especially in a noisy environment and on the phone.
• Difficulty hearing higher-pitched sounds and voices, like women's or children's voices.
• Difficulty hearing certain sounds, especially "s" or "th" sounds.
• Vertigo, dizziness, and a feeling of being off balance.

About Hashimoto’s and hypothyroidism

Hashimoto’s disease–also known as Hashimoto’s thyroiditis–is the most common autoimmune disease in the U.S. In any autoimmune disease, the immune system produces antibodies that inappropriately target our organs, glands, tissues or cells. Several autoimmune diseases are linked to hearing loss, including Hashimoto's.

In Hashimoto’s, antibodies target the thyroid and gradually impair its ability to produce thyroid hormone. Over time, it usually leads to the deficiency in thyroid hormone known as hypothyroidism.

The common signs and symptoms of Hashimoto’s and hypothyroidism include fatigue, weight gain, hair loss, dry skin, body aches, brain fog, cold hands and feet, depression, anxiety, menstrual irregularities, and constipation, among others.

To diagnose hypothyroidism, doctors use blood tests, including Thyroid Stimulating Hormone (TSH), and available “free” levels of thyroid hormones Thyroxine (Free T4) and Triiodothyronine (Free T3.) Elevated TSH and low Free T4 and Free T3 levels are evidence of hypothyroidism. A positive result on the Thyroid Peroxidase Antibodies (TPOAb) test can confirm a Hashimoto’s diagnosis.

The treatment for hypothyroidism is thyroid hormone replacement medication, usually generic levothyroxine, a synthetic form of the T4 hormone. (Synthroid and Levoxyl are well-known brands.) Brand-name Tirosint gel cap and Tirosint-SOL liquid levothyroxine are also available. Some patients benefit from combination replacement therapy, taking generic liothyronine or Cytomel, a synthetic T3 hormone, with their levothyroxine treatment. Finally, some hypothyroid patients feel best taking a different medication–natural desiccated thyroid (NDT)–because it includes natural forms of both T4 and T3 hormones. Apart from generic tablets, currently available brands of NDT include Armour and NP Thyroid.

Hypothyroidism and hearing loss: The connection

Hypothyroidism can actually cause sensorineural hearing loss, a connection that was first reported in medical studies all the way back in 1907. Despite this knowledge, more research is needed to determine just how common it is to have both conditions.

Regardless, there's good news for people with hearing loss who are newly diagnosed with hypothyroidism: Treating thyroid disease can help with hearing loss.

According to Sapna Shah, M.D., a board-certified endocrinologist with Paloma Health, "In the instance where thyroid dysfunction is causing hearing loss, studies find that hearing loss improves after a patient starts levothyroxine therapy.” In fact, one recent study found that six to twelve months of optimal thyroid hormone replacement treatment improved hearing in nearly 50 percent of the hypothyroid patients studied. Hearing loss was completely reversed in 15 percent of the patients!

Yet, even with proper treatment for thyroid disease, there's still an increased risk of hearing loss. One study estimated that 25 percent of hypothyroid patients have evidence of some degree of mild to moderate sensorineural hearing loss. Symptoms like tinnitus are more common with hypothyroidism, and hearing loss typically develops over time. 

Pat G. developed tinnitus 20 years ago when she was diagnosed with hypothyroidism. According to Pat, when she shared her tinnitus symptoms with her doctor, he told her he had tinnitus too and that there was nothing to be done.

“Then, just in the last year,” says Pat, “I noticed that I’m having trouble understanding conversations on TV, especially when they play loud background music. I know I need to see a hearing specialist soon. I had no idea any of this could be caused by my hypothyroidism!"

Sudden hearing loss

At least one study has indicated that people with hypothyroidism–especially those over 50–also face an increased risk of sudden sensorineural hearing loss (SSNHL). With SSNHL, also known as sudden deafness, rapid hearing loss occurs immediately, or within 72 hours. SSNHL requires immediate medical attention because early diagnosis and prompt treatment can help around 85 percent of patients regain some or all of their hearing. Interestingly, optimal thyroid treatment is also a factor in recovery from SSNHL; research shows that patients with higher levels of thyroid hormones have better SSNHL treatment results.

Finally, congenital hypothyroidism (CH) is also linked to hearing loss. Before and after birth, thyroid hormone is essential for the healthy development and functioning of the entire auditory system. Babies born with CH have a life-long risk of hearing loss three times higher than the general population. Mild hearing loss occurs in around 20 percent of CH patients, and once they reach early adulthood, an estimated 17 percent of CH patients require hearing support. Hearing experts recommend that CH patients receive regular screening for early detection of any hearing problems.

Hashimoto’s and hearing loss

Having an autoimmune disease like Hashimoto’s increases your risk of developing other autoimmune diseases, including several that can cause hearing loss.

Autoimmune inner ear disease

Patients with autoimmune Hashimoto’s face a higher risk of developing autoimmune inner ear disease, or AIED. In AIED, as antibodies target the inner ear, inflammation can lead to tinnitus and later progress to fluctuating, progressive, or sudden sensorineural hearing loss in both ears. Here’s a reason to seek evaluation immediately: When recognized and treated early, AIED can be reversible.

The link between hypothyroidism and Meniere's disease

Hashimoto’s and hypothyroidism patients are also at higher risk of developing Meniere’s disease, an autoimmune disease that affects the inner ear. Meniere’s disease symptoms include tinnitus, vertigo, a feeling of fullness in the ear, and sensorineural hearing loss. A recent study concluded that the rates of hypothyroidism in Meniere's patients are so high that all Meniere's patients should receive thyroid screening. That same study reported that after 12 weeks of optimal hypothyroidism treatment, all the Meniere’s patients studied experienced improvement in their hearing.

Other thyroid/hearing connections 

Many different drugs can cause hearing loss. You should also be aware of other hearing-related complications of thyroid conditions, including:

• Temporary or irreversible hearing loss and tinnitus are associated with the use of teprotumumab (Tepezza), a drug prescribed to treat thyroid eye disease.
• The antithyroid drug propylthiouracil (PTU), used to treat Graves' disease and hyperthyroidism, is associated with sudden sensorineural hearing loss.
• External beam radiation treatment, used to treat rare medullary thyroid and anaplastic thyroid cancers, is associated with hearing loss. (The more commonly used radioactive iodine [RAI] therapy for thyroid cancer is not associated with hearing impairment.)
• Pendred syndrome, a genetic condition associated with goiter–an enlarged thyroid–is associated with hearing loss that starts in infancy or early childhood. It is one of several rare diseases that cause hearing loss.

Your next steps?

According to audiologist Dr. Timothy Teague of Hearing Consultants, it's "possible to diagnose and treat thyroid issues before they impact your hearing." Familiarize yourself with the signs and symptoms of hypothyroidism, and if you have any concerns, see your health professional for thyroid blood tests. Endocrinologist Dr. Sapna Shah recommends that patients who want to get started right away order their own thyroid tests. According to Dr. Shah, "Testing for hypothyroidism is easy and affordable with an at-home thyroid test kit."

Many hearing experts recommend that patients get a hearing test and audiogram after a new diagnosis of hypothyroidism. The results can serve as a baseline to monitor hearing changes in the future.

Key steps to keep in mind

For people already diagnosed and treated with hypothyroidism, here are three key steps to keep in mind:

1. Pay attention to any signs and symptoms of hearing loss. We have a free online hearing test that can help detect early hearing changes.
2. Schedule periodic evaluations by a hearing health professional.
3. Always notify your health care provider immediately if you have any new or acute changes in your hearing.

Martha began noticing hearing issues around the time of her thyroid diagnosis more than a decade ago. "It wasn’t profound, and I figured I could adapt." The pandemic changed things for Martha, however. Says Martha: "Wearing face masks really highlighted how much I had come to rely on lip-reading and visual facial cues when communicating! I decided to get tested when my sorority sister–an audiologist–told me not to wait until my hearing degraded too much."

As for me, the next time I notice hearing problems, I won't wait a week. Instead, I'll take Dr. Shah’s advice: "If you notice that your hearing is worsening, I recommend meeting with your health care provider right away. Early diagnosis and treatment are essential."

To find a hearing healthcare professional at a clinic in your area, visit our directory of consumer-reviewed clinics. The sooner you reach out for help, the better your outcome will be.