The many faces of ocular syphilis: case-based update on recognition, diagnosis, and treatment

In recent years, syphilis (Treponema pallidum) has become increasingly prevalent in Canada, and as a result, rates of ocular syphilis are also rising. Classically, syphilis was seen primarily in men who have sex with men; now, it is increasingly seen in people of all age groups, sexes, and sexual orientations. We present a series of 26 cases of ocular syphilis from London, Ontario, 5 of which are discussed in detail to illustrate the varied presentations and diagnostic challenges of ocular syphilis. The presentations include uveitis, iris granuloma (gumma), retinitis (acute syphilitic posterior placoid chorioretinitis), vasculitis, optic neuritis, and serous retinal detachment. The 5 cases are mostly middle-aged heterosexual men and women without the typical risk factors that would alert the examiner to suspect syphilis. We emphasize the importance of testing for syphilis when assessing and treating inflammatory eye disease, regardless of demographics and known risk factors, given the increasing prevalence of this disease. Diagnosis of syphilis relies on serologic testing, which is complex and has undergone significant changes from historical reliance on the Venereal Disease Research Laboratory test. We provide an overview of the strategy and rationale for modern serologic testing. The mainstay of treatment remains intravenous penicillin G, with alternative antibiotics (e.g., ceftriaxone) being less effective.