Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) is causing coronavirus disease 2019 (COVID-19) pandemic worldwide since December 2019. The Reverse transcriptase-polymerase chain reaction (RT-PCR) test on nasopharyngeal swabs is generally used for diagnosing the disease. The pulmonary manifestations of COVID-19 are well recognized. In contrast, extra-pulmonary manifestations of the disease are not completely recognized yet. Headache, anosmia, ageusia, and erythematous rash are some of extra-pulmonary manifestations of COVID-19 (1). Furthermore, hearing loss is recently mentioned as a probable symptom of the disease. Some physicians noticed an unexpected increase of sudden sensorineural hearing loss (SSNHL) during the COVID-19 pandemic (2).
In a study by Freni et al, 50 patients with confirmed COVID-19 infection were evaluated with the Hearing Handicap Inventory for Adults (HHIA) and the Tinnitus Handicap Inventory (THI) questionnaires during the active phase of COVID-19 infection and 15 days after COVID-19 RT-PCR got negative. There was a significant difference in HHIA and THI questionnaire results between these 2 conditions (3). The authors suggested this might be due to neurotropism feature of the virus (3). The otologic symptoms associated with COVID-19 infection are hearing loss, tinnitus, and vertigo (3-8).
Dengen et al. reported a patient with COVID-19 disease and complete deafness in right ear and profound sensorineural hearing loss in left ear. Magnetic resonance imaging (MRI) revealed increased contrast enhancement of right cochlea. Due to signs of inflammatory process in cochlea that were seen on imaging and, in consequence, the high probability of soft tissue formation or ossification of cochlea, urgent cochlear implantation surgery was performed for the patient and the left ear was treated with 3 intra-tympanic triamcinolone injections (4).
A case series by Mustafa showed that high frequency pure-tone thresholds as well as transient evoked otoacoustic emission (TEOAE) amplitudes were significantly worse in asymptomatic COVID-19 PCR-positive cases than normal non-infected subjects (5). Another case series by Karimi-Galougahi et al. revealed sensorineural hearing loss which is probably associated with novel coronavirus infection (6). The hearing loss was more severe in high frequencies (6). A case series of 5 patients with SSNHL without any other COVID-19 symptoms, RT-PCR testing was positive in one of the patients. The authors suggested SSNHL could be the only presentation of COVID-19 infection (7).
In conclusion, SSNHL is probably one of the COVID-19 manifestations. It is important to establish diagnosis and begin treatment swiftly to prevent permanent hearing loss. More studies should be conducted to confirm SSNHL as one of COVID-19 manifestation.