Since the turn of the millennium a sustained outbreak of syphilis among men who have sex with men continues, approximately 20-50% of whom have concurrent HIV infection. In this paper we aim to explore the controversies that exist around the management of syphilis in HIV-positive individuals. Not only do HIV-positive people have different clinical manifestations of syphilis they have higher rates of asymptomatic neurological involvement, slower serological response to treatment and higher serological failure than HIV-negative individuals in most studies. Whether long-term clinical outcomes are different or affected by the antibiotic regimen selected remains to be established. The optimal antimicrobial regimen to treat syphilis in HIV is unknown due to a dearth of randomised controlled trial data. International guidelines state that the antibiotic management of syphilis is the same regardless of HIV status, with early syphilis treated with a single dose of benzathine penicillin G 2.4mU intrmuscularly. In practice, however, the majority of surveyed clinicians do treat HIV-positive people with more intensive antibiotics suggesting a lack of faith in guidelines. Factors which appear to affect the likelihood of developing neurological disease include CD4(+) count of <350 cells/μL, absence of antiretroviral therapy, rapid plasma regain (RPR) or venereal diseases reference laboratory titre (VDRL) >1:32, late-latent disease or lack of response to standard antibiotic treatment. We recommend a low-threshold for offering antibiotic treatment effective against neurosyphilis in HIV-positive people with syphilis, especially if they exhibit any of the above factors.
