Syphilis is a common but potentially very dangerous bacterial infection that can be transmitted sexually. If left untreated, syphilis can run rampant inside the human body, causing permanent organ damage or even death. Fortunately, though, it’s easily treated.

Learn more about syphilis, what it does to the body, how common it is and what can be done to prevent transmission of this potentially deadly bacteria.

In This Section

Syphilis Symptoms

Syphilis is caused by the bacteria Treponema pallidum, and this highly contagious sexually transmitted disease can infect the genitals, rectum or mouth and, though it’s rare, the eyes. While many people who contract syphilis will notice signs right away in the form of sores that appear on their bodies, many others will either not notice the signs or mistake them for something else.

Medical experts have long referred to syphilis as “The Great Pretender” because its symptoms are so easily mistaken for other diseases.

If left untreated, signs of syphilis are generally the same between men and women and will follow a three-stage course, with each stage having distinct physical signs:

  • Primary: The first sign of syphilis is a sore called a chancre (or canker) that appears at the location where the bacteria entered the body. Because this is often inside the body or in an area that’s not observed visually on a regular basis, the first sore or group of sores may not be noticeable. The first chancre or chancres last as many as six weeks and will clear up with or without treatment.
  • Secondary: Secondary syphilis is marked by skin rashes, which could include lesions around the mucous membranes of the body (mouth, vagina, anus and others). The rash or lesions can appear while the primary chancre outbreak is still healing or even weeks after it’s gone. A secondary syphilis rash typically is not itchy, but it will usually appear reddish-brown or rough-looking, typically on the palms of the hands and feet. It’s possible for this rash to appear on other parts of the body, and some are so faint they are not noticed. With or without rash, many people in secondary syphilis may also develop a brief illness that includes fever, sore throat, headaches, hair loss and fatigue. While these symptoms will disappear with or without treatment, in the absence of treatment, syphilis will proceed to its next stage.
  • Latent: When a person is experiencing latent syphilis, their bodies will show no signs that they are infected, and this stage can last for years without treatment. While the person’s body has no obvious signs, they remain infected and may still be able to transmit the disease to others during the early part of the latent phase.

Tertiary syphilis

Between 15% and 30% of people with untreated syphilis will develop complications, known as tertiary or late syphilis. Tertiary syphilis is incredibly dangerous and can develop as many as 30 years after the initial syphilis infection. Tertiary syphilis can damage vital organs, including the brain, liver and heart, and this damage may be irreversible even if the syphilis infection is treated. In some cases, syphilis can be fatal.


At any point, a syphilis infection can invade the body’s nervous system, causing serious damage, including paralysis, dementia, altered behavior and difficulty moving.

Ocular syphilis

Ocular syphilis can occur at any stage of the infection, with symptoms including vision changes or even permanent blindness.

Congenital syphilis

Infants born to mothers who are infected with syphilis can become infected, and in some cases, they can have permanent health problems, including deafness and dental deformities.

Syphilis Transmission

Syphilis spreads through direct contact with the skin sores of an infected person. These sores, called chancres (or cankers), can occur in, on or around the penis, vagina, anus, rectum or inside the mouth. Syphilis is transmitted when one of these sores contacts the skin — such as the vulva, anus, penis, vagina or mouth — of an uninfected person.

People who have primary and secondary syphilis are at their most contagious because they likely have open sores or sores that are healing but remain wet and can easily come into contact with an uninfected person during sex.

Transmission of syphilis can occur during vaginal, anal or oral sex, and climax is not necessary for the infection to spread to an uninfected person.

Syphilis Prevalence

Among sexually transmitted diseases whose prevalence rates are tracked by federal health officials (syphilis, chlamydia and gonorrhea), syphilis is the rarest of the three. However, syphilis rates today are at the highest they’ve been since the early 1990s.

The federal Centers for Disease Control and Prevention estimates that more than 115,000 were newly diagnosed with syphilis in 2018, including all stages of the infection. Rates of congenital syphilis also have risen sharply since the mid-1990s.

Primary and secondary syphilis reached a low in the early part of this century, but the rate of infections has risen every year for the past seven, climbing by some-400% between 2001 and 2018.

Primary & secondary syphilis infections per 100,000 people by year

1994 7.8
1995 6.2
1996 4.2
1997 3.1
1998 2.5
1999 2.4
2000 2.1
2001 2.1
2002 2.4
2003 2.5
2004 2.7
2005 2.9
2006 3.3
2007 3.8
2008 4.4
2009 4.6
2010 4.5
2011 4.5
2012 5
2013 5.5
2014 6.3
2015 7.4
2016 8.6
2017 9.4
2018 10.8

More than a dozen states have population-adjusted rates of primary and secondary syphilis that are higher than the overall rate for the United States, with Nevada’s rate of 22.7 infections per 100,000 people leading the nation. Vermont has the lowest rate, on the other hand, with 1.8 per 100,000 people.

Primary & secondary syphilis infections per 100,000 people by state

Nevada 22.7
California 19.2
Mississippi 15.5
Georgia 15.4
Arizona 14.9
New Mexico 14.6
Louisiana 14.3
Florida 13.7
Oklahoma 13.5
New York 13.4
Missouri 13.2
Maryland 12.2
Illinois 11
Washington 10.8
North Carolina 10.7
Oregon 10.2
Alabama 9.8
Arkansas 9.6
Rhode Island 9.1
Texas 9
Virginia 8.3
Tennessee 8.2
Kentucky 8.2
Massachusetts 8
South Carolina 7.6
Alaska 7.4
Michigan 6.5
Hawaii 6.4
Ohio 6.3
New Jersey 6.3
Pennsylvania 6.2
Nebraska 6.2
Colorado 6
Maine 5.5
Indiana 5.5
Utah 5.4
North Dakota 5.4
Minnesota 5.2
Kansas 5.2
New Hampshire 4.8
South Dakota 4.7
Montana 4.3
Wyoming 4
West Virginia 3.6
Delaware 3.1
Iowa 2.7
Idaho 2.7
Wisconsin 2.6
Connecticut 2.5
Vermont 1.8

At-Risk Groups

Anybody who is sexually active, particularly those who fail to use protection, are at risk of contracting syphilis, but the infection is far more common in a few specific groups within the population.

Men are much more likely than women to have syphilis, with an overall spread of more than 80% between the rate for men and the rate for women. This is largely owing to the fact that syphilis rates are highest in gay and bisexual men: About 64% of new primary and secondary syphilis cases in 2018 were diagnosed in men who have sex with men.

Primary & secondary syphilis infections per 100,000 people by age and sex

Age group Male Female
10-14 0.1 0.1
15-19 10.9 4.3
20-24 44.6 10.0
25-29 55.7 9.4
30-34 45.8 7.5
35-39 33.7 5.8
40-44 23.9 3.6
45-54 19 2
55-64 8.8 0.7
65+ 1.8 0.1
Total 18.7 3

Among racial and ethnic groups, primary and secondary syphilis rates are highest in African-Americans and Native Hawaiians/Pacific Islanders. Whites and Asians have the lowest syphilis rates among the ethnic groups studied.

Primary & secondary syphilis infections per 100,000 people by race or ethnicity

African-Americans 28.10
Native Hawaiians/Pacific Islanders 16.3
Native Americans/Alaska Natives 15.5
Hispanics 13
Multirace 9.4
Whites 6
Asians 4.6

Syphilis Complications

We’ve already discussed the potentially deadly health consequences untreated syphilis can have. In addition to those issues, syphilis can cause other complications depending on the infected person:

  • Other STDs: People who have syphilis are more likely to have other sexually transmitted diseases, either currently or at a previous time in their lives.
  • HIV: About half of gay and bisexual men with primary and secondary syphilis also have HIV, and syphilis-infected people are more likely to contract HIV if their syphilis infection causes broken skin.
  • Pregnancy: Congenital syphilis can lead to tragic consequences, such as stillbirth, miscarriage or death shortly after birth. In babies who do survive, they can have deformed bones, anemia, skin rashes, meningitis or brain and nerve disorders.
  • Cardiovascular disease: Untreated syphilis can damage heart muscle, and even after treatment, some damage may be permanent, including damage to heart valves, blood vessels and aorta.
  • Nervous system disorders: ISyphilis can cause chronic headaches, brain damage and vision or hearing loss.

Syphilis & Pregnancy

Syphilis is a major concern for pregnant women. While it’s possible for syphilis not to be transmitted from an infected woman to her baby either during pregnancy or birth, for babies who are infected with congenital syphilis, major, lifelong problems and even death can occur.

Congenital syphilis is more likely to occur in children of mothers who have early-stage syphilis, as their infections are more contagious during the primary and secondary stages, and all pregnant women should be screened at least once for syphilis, and women at high risk of syphilis should be tested repeatedly.

As many as 40% of babies born to women who have untreated syphilis will be stillborn or die from the infection as newborns. Women who are diagnosed with syphilis while pregnant can be successfully treated, and newborns who are diagnosed with congenital syphilis may be cured if they are treated right away.

Syphilis Testing

It’s not always possible to identify a syphilis infection on sight, even during a phase where a person may have open sores. However, syphilis remains a relatively uncommon STD, which is why only certain populations are urged to get regular testing or testing at specific intervals.

Still, if you suspect you have syphilis, either based on a possible exposure or some physical symptoms, you should consider getting tested right away.

Here is what the CDC recommends with regard to syphilis screening:

  • Pregnant women: All pregnant women should undergo a syphilis test at their first prenatal visit, and those who are at a high risk or have been exposed should be checked during the third trimester and again at birth.
  • Gay and bisexual men: Men who have sex with men should be tested at least annually for syphilis and on a more regular schedule, such as every six or three months, if they regularly engage in unprotected sex and/or have many non-monogamous partners.
  • HIV-positive people: Sexually active people who are newly diagnosed with HIV should be screened for syphilis and other STDs as a part of their initial HIV evaluation, and more regular testing may be necessary, depending on their risk factors.

The nature of syphilis and its nickname, Great Pretender, mean that the best way to find out if you are infected (and get treated) is to get yourself tested. You can get tested for syphilis even if you don’t see any open sores or rashes by providing a small sample of your blood, and those who do have sores can undergo a swab test from a sore.

There are many options for those who require syphilis testing, and some may be free or low-cost:

  • Planned Parenthood
  • Pharmacy clinic
  • Doctor’s office
  • Urgent care center
  • Community health clinics
  • Campus health clinic
  • At-home test kits

Syphilis Treatment

Syphilis is easily cured, particularly during the early stages, which is usually before any long-term damage has been done. A single injection of an antibiotic, most often penicillin, will cure a person with primary, secondary or early latent syphilis. For those with later stages of the infection, multiple doses of the antibiotic may be needed, but these people may have already experienced lasting damage that can’t be undone by antibiotics.

People who are undergoing treatment for syphilis should refrain from having sex, especially with new partners until any syphilis sores are completely healed, but syphilis treatment is not inoculating, meaning a person who has successfully been treated can become infected if exposed again later in life.

Syphilis Prevention

As with any disease but particularly with STDs, the best defense is a good offense, and the best way to prevent syphilis is by engaging in safe and responsible sexual practices. Of course, the only way to be 100% sure you won’t contract syphilis is not to have sexual contact with anybody else or to ensure the only sex you have is within the context of a long-term, sexually monogamous relationship.

Consistent use of condoms and dental dams can reduce the risk of transmission, but because syphilis can potentially be transmitted outside of the areas of the body protected by condoms or dental dams, it’s still necessary to be careful and thoughtful even if you use condoms.

Remember that while syphilis can usually be treated very easily, it is possible to contract the disease even if you’ve been treated for it once.


Though syphilis is far rarer than other STDs like gonorrhea or chlamydia, it remains an incredibly dangerous infection, with the potential to cause serious damage or even death to the infected person. With rates of primary and secondary syphilis as well as congenital syphilis rising, now is the time for vigilance, which means getting tested and, if necessary, cured.

Additional References

  • Centers for Disease Control and Prevention, Sexually Transmitted Diseases (STDs), Syphilis, Facts & Brochure, Syphilis - CDC Fact Sheet (Detailed). (2019.) Retrieved from
  • Centers for Disease Control and Prevention, 2015 STD Treatment Guidelines, Screening Recommendations and Considerations Referenced in Treatment Guidelines and Original Sources. (2015.) Retrieved from
  • Centers for Disease Control and Prevention, Syphilis, Syphilis Treatment and Care. (2019.) Retrieved from
  • Centers for Disease Control and Prevention, Sexually Transmitted Disease Surveillance 2018, Table 1. Sexually Transmitted Diseases — Reported Cases and Rates of Reported Cases*, United States, 1941–2018. (2019.) Retrieved from
  • Centers for Disease Control and Prevention, Sexually Transmitted Disease Surveillance 2018, Table 26. Primary and Secondary Syphilis — Reported Cases and Rates of Reported Cases by State, Ranked by Rates, United States, 2018. (2019.) Retrieved from
  • Centers for Disease Control and Prevention, Sexually Transmitted Disease Surveillance 2018. Table 35B. Primary and Secondary Syphilis — Rates of Reported Cases* by Race/Hispanic Ethnicity, Age Group, and Sex, United States, 2018. (2019.) Retrieved from

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