Syphilis and human immunodeficiency virus coinfection: More than the sum of its parts

Human immunodeficiency virus (HIV) and syphilis are both sexually transmitted diseases and, as such, are often seen as coinfections. Recently, there has been an increase in syphilis rates among men who have sex with men, many of whom are also infected with HIV. Individuals coinfected with syphilis may transmit HIV more frequently because of increased viral shedding in genital secretions. Individuals with syphilis monoinfection may be more susceptible to HIV infection because of disruption of the mucosal barrier. Serologic diagnosis of syphilis in HIV-infected persons, although usually reliable, may be difficult to interpret because of aberrant levels of antibodies. Patients coinfected with both HIV and syphilis are more likely to present with multiple chancres and progress to symptomatic neurosyphilis. Syphilis treatment failures and relapses occur more frequently in HIV-infected persons mandating close follow-up of clinical symptoms and serologic titers among these patients. Penicillin remains the drug of choice, with no studies demonstrating a more effective regimen among HIV-infected persons.