What is syphilis?
Syphilis infection is a sexually transmitted infection caused by the bacteria Treponema pallidum.

How common is syphilis?
In 2000, syphilis rates in the US reached the lowest level since reporting began in 1941.
Beginning in 2001, however, syphilis rates have increased yearly. In 2013, the total case counts (all stages) were the highest recorded since 1996. From 2012 to 2013, there was a 13.1 increase in overall cases.1
Most cases of Primary and Secondary Syphilis in 2013 (75%) were associated with men having sex with men (MSM). In 2013 the highest rate of syphilis was found in men ages 20 – 29.1 In 2013, 20% of all newly diagnosed cases were in young people, ages 15 – 24.2
Babies, who can be infected if their mother has syphilis, have also had more syphilis infections in recent years. The rate of congenital syphilis increased in again in 2013.1

How is syphilis spread?
Syphilis infection can be spread through vaginal, anal, and oral sex. It can also be spread through skin to skin contact. If a woman has syphilis infection while she is pregnant, she can pass it to her baby before it is born.
Syphilis can be spread to other people during the primary, secondary, and early latent periods (see below.)

Does syphilis cause symptoms?
Syphilis has often been called “The Great Mimicker” because its symptoms look like those of other diseases. Therefore, it has been difficult to diagnose syphilis in the past based on symptoms.

The first stage of syphilis is called primary syphilis. During primary syphilis, one or several sores, called chancres, may appear where the infection entered the body. These sores are usually found on the genitalia, but may be found near the mouth or on other skin that contacted an infected person. Chancres are painless ulcers that have raised edges. The chancres will heal without medicine after about 3 to 6 weeks. If the infected person does not realize that they have syphilis and get treated, the infection goes into the second stage of syphilis, called secondary syphilis.

Secondary syphilis occurs while the chancre is healing or soon after it has healed and involves flu-like symptoms and a skin rash. The rash looks different in different people, but often includes spots on the palms and soles of the feet. Patchy lesions may also appear inside the mouth and around the genitals. If the syphilis infection is not treated in this stage, it progresses into a third stage called the early latent period

In the early latent period, no symptoms may occur, but the infection is still present in the body. By this time, the infection has spread to many different parts of the body. Without treatment, the syphilis infection may progress to late latent syphilis, also known as tertiary syphilis.

During the tertiary stage, the long term damage of the syphilis infection begins to show. An infected person may begin to notice brain and nerve damage, heart damage, blood vessel damage, or other effects throughout the body. The symptoms will depend on what part of the body the syphilis infection has damaged.

Are there any treatments available for syphilis?
Syphilis is treatable with antibiotics, such as penicillin. One dose will treat syphilis in an early stage, but more doses are needed for syphilis infections that have been present for longer periods of time. Damage done to the body before the infection is treated may be permanent.

What complications can result from syphilis?
Syphilis can damage the heart, blood vessels, brain, nerves, eyes, bones, joints, liver, and other organs. It can even cause death. In 2015 there was an increase in ocular syphilis (eye), which can lead to permanent blindness.3

Women who are infected with syphilis when they are pregnant are at increased risk of miscarriage or stillbirth. If a baby is born with syphilis and is not treated early, the baby is at increased risk of seizures, developmental problems, and death.

Does syphilis infection affect the spread of HIV?
When a person has a syphilis infection, they are more likely to acquire HIV from an infected sexual partner. Syphilis can increase the chances of getting HIV by 2- to 3- fold.4
One study showed a 4-fold increase in the chance of acquiring HIV in syphilitic men who have sex with men.5

Can syphilis infection be prevented?
Yes; syphilis infection can be prevented by refraining from sexual activity until a person is in a lifelong, mutually monogamous relationship with an uninfected partner. Pregnant women should be screened and treated for syphilis infection to prevent the spread of syphilis to their babies.


A syphilis chancre can occur wherever the skin contacted the infection. This man has a chancre on his lip.


Note the chancre on the lower part of the abdomen.


Note the chancre on the inner side of the labia.


This is an example of the rash of secondary syphilis that may occur on the palms and soles of an infected person.

his image shows the “mucous patches” that may occur in the mouth and other mucous membranes during secondary syphilis.

1. Centers for Disease Control and Prevention, “2013 STD Surveillance Syphilis”,, retrieved Jan 2015
2. Centers for Disease Control and Prevention, “Sexually Transmitted Infections Among Young Americans,”, retrieved Jan 2015.
3. Center for Disease Control & Prevention, “Clinical Advisory: Ocular Syphilis in the United States,”, retrieved 4/3/2015
4. Sexton J, Garnett G, Rottingen JA. Metaanalysis and metaregression in interpreting study variability in the impact of sexually transmitted diseases on susceptibility to HIV infection. Sex Transm Dis 2005;32(6):351-357.
5. Xu JJ, Zhang M, Brown K, et al. Syphilis and HIV seroconversion among a 12-month prospective cohort of men who have sex with men in Shenyang, China. SexTransm Dis 2010, 37(7):432-439.



Updated: May 2015