A doctor diagnoses Cogan's syndrome after finding the typical combination of problems associated with this disease in the eye and inner ear. Until both the eye and the inner ear are affected, the diagnosis may be uncertain. Either area may be affected first, or the eye and ear problems may develop at the same time.
Your doctor will want to rule out an infection (especially syphilis, tuberculosis, viral infection and chlamydia) or another rheumatic disease (including rheumatoid arthritis, sarcoidosis and Granulomatosis with polyangiitis (Wegener's granulomatosis)) as the cause of your symptoms. Your doctor will refer you to an ophthalmologist for an eye examination to look for eye problems, including a condition called interstitial keratitis, which is inflammation of the cornea, the transparent covering of the eye. Your doctor also will want to evaluate your nervous system (for example, reflexes, strength and sensation), and check your ears by testing hearing, balance and inner ear function.