Cogan's Syndrome

Cogan's syndrome affects the eyes and the inner ears, and is understood as a rare form of autoimmune vasculitis, inflammation of small and medium blood vessels. The immune system appears to inflame eye tissue such as the cornea, causing interstitial keratitis, alongside the structures of hearing and balance in the inner ear, with cytokines and immune cell activity thought to drive tissue damage in both sites. A 2025 comprehensive review described it as affecting mainly young adults and noted that roughly 7 in 10 people with the condition also have some form of systemic vasculitis.

Because the literature is limited to case series and small cohorts, precise prevalence figures are not well established, and there are no specific diagnostic biomarkers, so it is typically diagnosed by ruling out other conditions. Because it can threaten both vision and hearing, it needs prompt specialist care.

Common signs

Eye redness, pain, tearing, and light sensitivity, together with inner-ear symptoms such as hearing loss, ringing in the ears, vertigo, and dizziness. Fever, headache, and joint pain can also occur.

This is a plain-language summary for orientation, not a diagnosis. Mechanisms are described as current understanding, not settled fact. Work with your own clinician for your care.