Prolonged prodrome, systemic vasculitis, and deafness in Cogan's syndrome

Cogan's syndrome is a rare, multisystem disease which occurs predominantly in children and young adults. It was originally described as the combinatio n of interstitial keratitis and audiovestibular disturbance, but other form s of ocular disease, as well as systemic vasculitis, have since been recogn ised as part of the syndrome. Diagnosis can be difficult if the various man ifestations occur separately, but early recognition is important because pr ompt treatment may prevent deafness. Two cases are presented here illustrat ing the features of this disease, and providing histological evidence of sy stemic vasculitis in both.