Chlamydia pneumoniae infection as a trigger for a Cogan's syndrome.

Cogan's syndrome is often preceded by upper respiratory tract symptoms. The only reported specific agent possibly involved in pathogenesis of the Cogan's syndrome was Chlamydia pneumoniae. Positive IgA, IgM and IgG antibodies against C. pneumoniae in our patient suggest possibility of Chlamydia's role as a trigger for the vasculitis.