Cogan's syndrome: an audiovestibular, ocular, and systemic autoimmune disease.

Cogan's syndrome is an immune-mediated systemic disorder characterized by ocular and audiovestibular inflammation. Although interstitial keratitis in the absence of an infectious cause is the classic form of eye involvement, other nonspecific inflammatory eye diseases can also occur, often making prompt diagnosis of the underlying disease challenging. The audiovestibular disease is difficult to treat and can lead to profound hearing loss. A poor outcome, especially complete hearing loss, can sometimes be prevented through a timely recognition and initiation of glucocorticoid therapy at the onset of the disease.