Autoimmune inner ear disease (AIED): A diagnostic challenge

Autoimmune inner ear disease (AIED) has been defined as a condition of bilateral sensorineural hearing loss (SNHL), caused by an 'uncontrolled' immune system response. The inner ear can be the direct target of the immune response, but it can be additionally damaged by a deposition of circulating immune complexes or by systemic immune-mediated diseases. The clinical expression of immune-mediated inner ear disease shows a progressive bilateral and asymmetric SNHL profile, which typically benefits from a steroid and immunosuppressive therapy. The onset of AIED is between 3 and 90 days. Cochlear symptoms can be associated with vestibular disorders and in 15%-30% of cases, AIED occurs in the contest of a systemic autoimmune disease. Currently, the onset of immune-mediated SNHL is not a well-understood process and the pathogenetic mechanisms of AIED remain unclear. Furthermore, there are no standardized diagnostic criteria or reliable diagnostic tests for the diagnosis of AIED. Hence, the definition of immune-mediated cochleovestibular disorders is a challenging diagnosis based on exclusion. A close collaboration between otolaryngologists, audiologists and rheumatologists is recommended, in order to achieve the multidisciplinary management of this rare entity, since an early AIED identification and a prompt medical treatment might result in acceptable hearing outcomes. The paper describes the clinical features of AIED and offers a diagnostic flow-chart to use in the clinical assessment of this condition.