It’s been well-established that the telltale symptoms of COVID are fever, a dry cough, shortness of breath, loss of smell or taste, headache, chills, sore throat, and muscle pain. To our aging population (those over 70), you can add gastrointestinal issues (diarrhea, nausea, abdominal pain) and confusion.
Dermatologists have even reported that certain skin conditions are reflective of COVID including “COVID toes,” a skin condition that resembles chilblains. Symptoms include pink, red or purple lesions on the toes or feet – and sometimes, the hands.
And now, according to the April, 2020 edition of American Journal of Otolaryngology, COVID-19 can cause hearing loss.
The first case appeared in Thailand where an older female, diagnosed with COVID-19, did, indeed, develop hearing loss. Interestingly, her respiratory function improved yet her hearing loss continued (more on the persistence of hearing loss in COVID-19 patients later).
Soon thereafter, a small group of asymptomatic COVID-19 patients in Egypt, aged 20-50 years, found that they suffered hearing loss, as well. None had ever reported a history of hearing problems. It was concluded that “the absence of the major symptoms does not guarantee a safe, healthy cochlear function.” A later study of COVID-19 patients in Iran with mild symptoms, aged 22-40 years, found each suffered mild-to-moderate hearing loss including tinnitus and vertigo.
In general, it was concluded that COVID-19 directly contributed to hearing loss in the aforementioned patients.
Viral-Induced Hearing Loss Is Nothing New
Why does the virus attack the cochlear or inner ear?
Other viruses that cause hearing loss
Measles, mumps, meningitis, and coronaviruses are known to cause damage to the nerves that carry soundwaves from the spiral-shaped cochlear to the brain. While SARS-CoV-2 (COVID-19) is one of those viruses, it should be noted that there haven’t been any reported cases of hearing loss in patients with SARS-CoV-1 or MERS-CoV.
The fact that viruses, in general, cause hearing loss is not new. At times, viruses will interfere with inner ear functioning and cause hearing loss. There’s not a lot of research indicating how long the hearing loss persists but if we follow the trends of other viruses, the hearing loss should be temporary.
Examples of Other Viruses Causing Hearing Loss
Herpes simplex virus type 1 (HSV-1)
Can be found in the vestibular nerve of the inner ear infected patients with vertigo
Herpes zoster virus
If the virus gets into the facial nerves closest to the ear, it can cause facial paralysis and hearing loss
Congenital cytomegalovirus infection
Mostly affects the unborn and infants. Can cause hearing loss, vision loss, intellectual disability, microcephaly (small head), lack of coordination, and seizures
Can get into the middle ear of infected patients with otosclerosis and cause hearing loss. Otosclerosis is an overgrowth of one of the three bones in the inner ear (malleus, incus, and stapes)
Human immunodeficiency virus (HIV)
Symptoms include ear fullness, dizziness, hearing loss, and tinnitus
COVID-19 (SARS-CoV-2, Coronavirus) Can Cause Hearing Loss: A Summary
- Hearing loss can occur in symptomatic or asymptomatic patients with COVID-19
- COVID-19 disrupts the flow of sound waves from the cochlear hair cells in the inner ear to the brain
- COVID-19 can also affect auditory centers in the temporal lobe and brainstem
- Mild to moderate hearing loss can appear suddenly, without warning, especially in younger people
- If COVID-19 is similar to other viruses, the hearing loss should not be permanent
- Drugs used to fight COVID-19 (Azithromycin, Remdesivir, Favipiravir, and Lopinavir) can cause hearing loss (ototoxicity)