A number of viral infections can cause hearing loss. Hearing loss induced by these viruses can be congenital or acquired, unilateral or bilateral. Certain viral infections can directly damage inner ear structures, others can induce inflammatory responses which then cause this damage, and still others can increase susceptibility or bacterial or fungal infection, leading to hearing loss. Typically, virus-induced hearing loss is sensorineural, although conductive and mixed hearing losses can be seen following infection with certain viruses. Occasionally, recovery of hearing after these infections can occur spontaneously. Most importantly, some of these viral infections can be prevented or treated. For many of these viruses, guidelines for their treatment or prevention have recently been revised. In this review, we outline many of the viruses that cause hearing loss, their epidemiology, course, prevention, and treatment.
A number of viral infections can cause hearing loss. A baseline knowledge of these viruses is critical in the recognition of their involvement in hearing loss in affected patients. Because some of these infections and the hearing loss that they cause can be treated with specific therapy, knowledge of these entities becomes even more important in the evaluation and management of patients with hearing loss. Hearing health care providers may encounter frequent questions from parents of children with hearing loss, questioning whether specific viral infections or vaccinations for these viruses have caused their child’s hearing loss.
In this review, we have discussed some of the more commonly known viral causes of hearing loss as well as a few emerging viral infections that ultimately may be shown to be frequent causes of deafness. Some cause congenital hearing loss due to infection of the fetus in utero. Others cause hearing loss as a result of infection in childhood or adulthood. Hearing loss following viral infection is often sensorineural, although it may be mixed (CMV, measles) or conductive (measles). Auditory system damage is typically intracochlear; however, some viruses can affect the auditory brainstem as well. Mechanisms of injury to the peripheral auditory system can include direct viral damage to the organ of Corti, stria vascularis, or spiral ganglion; damage mediated by the patient’s immune system against virally expressed proteins (CMV); and immunocompromise leading to secondary bacterial infection of the ear (HIV, measles). Hearing loss due to HZO or CMV infection can be treated medically with stabilization or improvement in hearing thresholds. Common childhood vaccines can prevent several of the viral infections discussed within this review and should be recommended to patients and parents. The incidence of hearing loss following vaccination with live-attenuated virus vaccines, such as the MMR and MMRV, is extremely rare. Rehabilitation of hearing loss due to other viruses typically involves hearing aids, with cochlear implantation for patients with severe to profound hearing loss.