Objective: To report our experience on a multicentre series of 32 patients with either typical or atypical Cogan's syndrome, to combine our results with a detailed review of the literature, and to compare the clinical manifestations of typical and atypical Cogan's syndrome.
Methods: Patients were identified from a survey conducted with physicians affiliated to the French National Society for Internal Medicine, and were classified into typical or atypical Cogan's syndrome according to the Haynes criteria. Clinical data were collected in a standardized manner. A comprehensive literature review using the Medline database and the reference lists of identified articles was performed.
Results: Seventeen patients had typical Cogan's syndrome and 15 had atypical Cogan's syndrome. Apart from non-syphilitic interstitial keratitis, the ocular manifestations of patients with atypical Cogan's syndrome were mainly uveitis and episcleritis. All but one patient presented with Ménière-like syndrome, and at the end of follow-up 11 were deaf and 19 additional patients had developed a significant decrease in auditory acuity. Twenty-five patients (78%) developed systemic manifestations, including aortitis in four. Comparison of typical and atypical Cogan's syndrome showed that some systemic manifestations were more common in atypical Cogan's syndrome, but these differences may be explained by reporting bias in the literature.
Conclusion: Differences regarding the associated systemic manifestations of typical and atypical Cogan's syndrome may reflect reporting bias in the literature. However, the diversity of the ocular and audiovestibular manifestations and the acceptable lengthy delay between the two types of involvement in atypical Cogan's syndrome should make one cautious before accepting this diagnosis as the diagnosis may mimic various other systemic diseases.