Background:  The incidence of syphilis in HIV-infected men who have sex with men (MSM) continues to increase. Rather than being diagnosed at the time of symptom presentation, these cases are often discovered later by routine serologic screening. The aim of this study was to describe the clinical presentations of syphilis in HIV-infected MSM and time to diagnosis and initiation of treatment.

Methods:  We conducted a retrospective chart review of all HIV-infected MSM diagnosed with incident syphilis at our HIV clinic from January 1, 2000 to July 31, 2007. Patients were included if they had a prior documented negative syphilis serology and no history of syphilis. The medical record from the time of the last negative serology to syphilis diagnosis (maximum 1 year) was reviewed for symptoms of syphilis. Kaplan-Meier and Cox proportional hazard methods were used to calculate the predictors of a complete serologic response to treatment.

Results:  We included115 patients:  median age of 38 (IQR 34 to 43), median CD4 of 403 cells/μL (IQR 267 to 512), and 48 (42%) with HIV RNA <400 copies/mL. There was a median of 268 days (IQR 144 to 399) from the prior negative syphilis serology to the diagnostic test. The table shows symptoms occurring in at least 10% of subjects, proportion with a delay in diagnosis from presentation with symptom, and median delay. 52 (48%) had a delay in diagnosis. The median time to negative serology after treatment was 408 days (IQR 329 to 645). Predictors of longer time to negative serology include a higher titer at diagnosis (p = 0.001), late latent syphilis (p = 0.02) and HIV RNA level >400 copies/mL (p = 0.09). Among patients with primary, secondary, or early latent syphilis, 1 vs 3 intramuscular injections of benzathine penicillin G was not associated with the time to negative syphilis serology (p >0.5); 28 (24%) became re-infected with syphilis.

Conclusions:  The presentation of syphilis in HIV-infected MSM was characterized by a wide range of symptoms that were frequently not recognized as syphilis. A higher level of suspicion among providers and more frequent serologic testing of HIV-infected men are warranted.