Cogan's syndrome: present and future directions.

Cogan's syndrome, typified by the combination of interstitial keratitis and immune-mediated sensorineural hearing loss, is a rare condition, and commonly associated with a diagnostic delay. Using a standard search protocol, we review the literature to date, focusing on a number of key areas pertaining to diagnosis, presentation and treatment. Using a case illustration of atypical disease which led to fulminant aortic regurgitation, we highlight the need for continued and collaborative research in order to identify negative prognostic factors and thus tailor therapeutic regimens. Atypical Cogan's syndrome is more commonly associated with systemic manifestations than typical disease, and may be refractory to immunosuppressive treatment. We discuss the application of laboratory (e.g antibodies targeting inner ear antigens) and radiological (PET-CT) aids to disease confirmation and detection of sub-clinical vascular inflammation. As illustrated by the included case description, some patients remain refractory to intense immunosuppression and delineation of adverse prognostic factors which may direct treatment, perhaps including the use of PET-CT, will contribute in the future to improving patient outcomes.