Aetiology of Sudden Sensorineural Hearing Loss: Autoimmune Hypothesis

Acceptance of immune-mediated inner ear disease (IMIED) as its own clinical entity was first published in 1979 [1], based on the clinical profile and response to steroid and immunosuppressive drug treatment. In animal models, it has been possible to establish an implication of the theories usually accepted in the aetiopathogenesis of idiopathic sudden sensorineural hearing loss (ISSNHL): vascular, viral and autoimmune. As a result, the viral infection triggers not only an involvement of the cochlear microvascularisation but also a powerful immune response inside the inner ear with the result of a fibro-osseous matrix, responsible for irreversible damage to the auditory organ. These lesions have been described in various systemic autoimmune diseases, in which a viral infection can be the triggering event of this disease. However, the low profitability of serological studies to identify different viruses in sudden hearing loss discourages their inclusion in the study protocol of this entity [2, 3].