Causes of hearing loss

Can COVID-19 cause hearing loss?

Current research shows that most people who contract COVID-19 do not experience hearing loss as a symptom. However, there is some evidence to suggest that COVID-19 can cause hearing loss in rare cases.^5,7

Recent research looked into the link between COVID-19 and audio-vestibular symptoms across 24 studies.⁵ Scientists found that in people who were infected by COVID-19, 7.6% experienced hearing loss, 14.8% experienced tinnitus (ringing in the ears) and 7.2% experienced rotatory vertigo (feelings of spinning and dizziness).⁸

The WHO has now also linked ‘hearing issues’ to long Covid, identifying it as a symptom in their recent definition of the post-COVID-19 condition.⁶ In some rare cases then, coronavirus can be known to impact your hearing, as well as your balance.

Can high blood pressure affect your ears?

Hypertension can accelerate the ‘wear and tear’ of the auditory system in your ears. Research has shown that long-term hypertension is also linked with fatty plaque build-up in your blood vessels, depriving your ear and internal structures of much-needed blood and nutrients.

The end result is that high blood pressure over both the short and long term can have a noticeable effect on your hearing. 

The current theory is that very high blood pressure can permanently damage the tiny blood vessels in your ears, reducing your ability to hear the full spectrum of sound.

Glucose levels

The effect that diabetes can have on your blood vessels and nerves can cause issues with your ears, sometimes causing an ‘injury’ to the inner ear which can affect your hearing.⁹,¹⁰ Unstable blood glucose levels can also put you at greater risk of hearing loss.¹²

While it’s unclear exactly what happens, scientists have found that high blood sugar levels can damage the small blood vessels in the inner ear, affecting blood circulation in that part of your ear.¹¹ Your hearing can also be affected if you have low blood sugar.¹⁵ 

Research has found that this is because low blood sugar is one of the factors that can create a chemical imbalance in the fluid found in your ear.¹⁶,¹⁷ This fluid has a very specific make-up which allows the cochlea to function properly, so if this is altered it can change the way your ear processes sounds.

If you have diabetes you may start to notice subtle changes to your hearing, particularly with high-frequency sounds.¹³,¹⁴ For example, you may find vowel sounds easy to identify, but the letters f, s, t and z, may be more difficult for you to notice. Or sounds with higher octaves, like birdsong, may not be as clear.

Ear infections

People with diabetes have an increased risk of infection and related complications. One type of common ear infection is malignant otitis externa, which only affects diabetic people.

This is an infection of the external ear canal and skull base, which usually affects older people with diabetes.¹⁸ The infection is caused by bacteria and can spread to surrounding areas (like the jawbones or face) if it’s left untreated.¹⁹

Sudden hearing loss can be a symptom of this infection, so you should get your ears checked out quickly if you are diabetic and experience sudden hearing loss. Diabetic people can also be at a higher risk of developing inner ear infections due to excess insulin.²⁰ So controlling your insulin levels and having regular check-ups are important to avoid both of these types of infection.²¹,²²

If you have diabetes you may experience hearing loss to some extent, but maintaining stable blood sugar levels should help you reduce the impact of your diabetes on your hearing. It’s also important to seek early treatment for injury and infection, protect your ears from prolonged exposure to high noise levels and quit smoking as it can increase the risk of hearing loss.²¹ 

If you suspect any change in your hearing, it’s a good idea to book a free appointment to get your hearing checked by an audiologist. Read about the symptoms of hearing loss here.