Syphilis is a sexually transmitted infection (STI) caused by the bacterium Treponema pallidum. It’s often called “the great imitator” because so many of its signs and symptoms look exactly like those of other diseases.
How Is It Spread?
Syphilis passes from person to person through direct contact with a syphilis sore. Sores (called chancres) occur mainly on the external genitals, vagina, anus or in the rectum. Sores also can occur on the lips and in the mouth.
Transmission occurs during vaginal, anal or oral sex. Pregnant women with syphilis can pass it to the baby.
Syphilis cannot be spread through contact with toilet seats, doorknobs, swimming pools, hot tubs, bathtubs, shared clothing or eating utensils.
Syphilis is divided into stages:
- Primary — One or more painless, reddish-brown sores appear on or near the genitals.
- Secondary — A skin rash develops anywhere on the body. Flu-like symptoms, such as mild fever, fatigue and sore throat, appear.
- Latent — No signs or symptoms.
- Tertiary — Late-stage symptoms include brain damage, mental illness, blindness, heart disease and death.
The best way to avoid transmission of sexually transmitted diseases, including syphilis, is to abstain from sexual contact or to be in a long-term mutually monogamous relationship with a partner who is known to be uninfected.
Syphilis can occur in both male and female genital areas that are covered or protected by a latex condom, as well as in uncovered areas. Correct and consistent use of latex condoms can reduce syphilis risk only when the infected area or site of potential exposure is protected.
Transmission of a STI, including syphilis, cannot be prevented by washing the genitals or by urinating or douching after sex.
Any unusual discharge, sore or rash — particularly in the groin area — should be a signal to refrain from having sex and to see a doctor immediately.
A single injection of penicillin, an antibiotic, will cure a person who has had syphilis for a short time (typically, less than a year). Additional doses are needed to treat someone who has had syphilis for longer.
For people who are allergic to penicillin, other antibiotics are available. Treatment will kill the syphilis bacterium and prevent further damage, but it won’t repair damage already done.
Because effective treatment is available, it’s important to be screened for syphilis regularly if your sexual behaviors put you at risk for STIs.
Persons who receive treatment must abstain from sexual contact with new partners until syphilis sores are completely healed. Persons with syphilis must notify their sex partners so they also can be tested and receive treatment if necessary.
Syphilis and HIV/AIDS
Genital sores (chancres) caused by syphilis make it easier to transmit and acquire HIV infection sexually. When syphilis is present, your risk for acquiring HIV increases 2 to 5 percent.
Last Reviewed: September 2019