Syphilis skyrockets, diagnosis delayed in HIV-positive men

The diagnosis of syphilis is often delayed in HIV-positive patients, as it is characterized by a wide range of symptoms that may not be recognized as infection with Treponema pallidum, according to the division of international medicine and infectious diseases, Cornell University, New York.

After declining to an all-time low in 2000, the rate of syphilis in the United States rose from 3 per 100,000 populations in 2001 to 5.7 per 100,000 in 2006. Syphilis has increased particularly dramatically among men who have sex with men (MSM), who made up 4% of cases in 2000 but represented 64% of cases in 2006, reported in a poster session at the 15th Conference on Retroviruses and Opportunistic Infections.

Nationwide, approximately 60% of cases of syphilis now are seen in HIV-positive, urban MSM, but in New York City, 97% of syphilis cases are in MSM. To more fully characterize this coinfected population in New York City, they undertook a retrospective chart review of all HIV-positive MSM diagnosed with incident syphilis at the Cornell HIV clinic between January 2001 and December 2007.

A total of 118 cases of syphilis were identified. Stage at diagnosis was primary in 8 patients, secondary in 80, and early latent in 17, and late latent in 13. Three patients had neurosyphilis.

Median age of the patients was 38 years. A total of 33% were white, 30% were black, 34% were Hispanic, and the rest were classified as “other”.

The HIV RNA level was less than 400 copies/mL, in 56%, and median CD4 count was 399 cells/mm3. Rapid plasma regain (RPR) titer at the time of syphilis diagnosis was 1:8 or lower in 17%, 1:16 to 1:32 in 36%, 1:64 to 1:128 in 37%, and higher than 1:256 in 10%. Clinical presentations were varied, and the diagnosis was delayed in nearly half of the patients over all. A total of 96% of patients had a fourfold decrease in RPR titer at 1 year, but reinfections were common, being seen at a rate of 10% per year.

A multivariate analysis showed that higher baseline RPR titer and diagnosis of latent syphilis were associated with a longer time until the RPR titer became negative, it was reported at the meeting, which was sponsored by the Foundation for Retrovirology and Human Health and the Centers for Disease Control and Prevention.

Different treatment regimens — one or three doses of 2.4 million U benzathine penicillin, or doxycycline 100 mg twice daily for 30 days — were not associated with a longer time until RPR negatively, the researchers found.

Cases of early syphilis in this population are often not identified, so a higher index of suspicion is needed among clinicians. More frequent serologic testing also is warranted. –Charles C. Chante, MD (The Philippine Star)