What Is Syphilis? Symptoms, Causes, Diagnosis, Treatment, and Prevention

Syphilis is a bacterial infection that’s typically spread through sexual contact.

The first sign of syphilis is most commonly a painless sore, called a chancre, that develops where the bacteria entered the body. The chancre typically appears within three weeks from the time of exposure. It is usually in the area of the genitals, rectum, or mouth, and it can go unnoticed if it is hidden inside the body.

The infection spreads from person to person when a person touches these sores with their skin or mucous membranes.

Syphilis can be difficult to diagnose because after the initial infection the bacteria can lie dormant in the body for years before becoming active again. With no visible symptoms, the only way to know that you have syphilis is to be tested for it, which usually involves having a blood sample taken. (1)

Syphilis can be a serious, even life-threatening illness if it goes untreated. It’s especially dangerous when passed from an infected mother to her infant during pregnancy or childbirth.

With the number of cases of syphilis, including congenital syphilis, on the rise in the United States and elsewhere in the world, the Centers for Disease Control and Prevention (CDC) is recommending annual or even more frequent screenings for those individuals at high risk, and numerous state and local health departments are mounting awareness campaigns. (2)

Fortunately, there are several very effective treatments available to kill the bacteria that cause syphilis, and the infection is easily curable in adults when treated early. It can be treated at later stages as well, but treatment cannot reverse any organ damage the disease may have already caused.

A person can have syphilis and not see or feel any symptoms, which is one reason it’s such a common infection. It’s also easy to confuse syphilis with other things, such as pimples or rashes. (3)

The symptoms of syphilis are different depending on what stage the disease is in.

Primary Stage

There may be single or multiple sores, which are usually firm, round, and painless and can often go unnoticed. The sore(s) typically last three to six weeks with or without treatment. Even after the sore goes away, treatment is necessary to stop the infection from progressing to the secondary stage. (4)

Secondary Stage

This stage usually begins with a rash on one or more areas of the body. The rash can appear as rough, red or reddish-brown spots, but sometimes it’s very faint and not noticeable. Other symptoms of syphilis that can come in the secondary stage include the following: (4)

• Sores in the mouth, vagina, or anus
• Fever
• Swollen lymph glands
• Sore throat
• Patchy hair loss
• Headaches
• Weight loss
• Muscle aches
• Fatigue

Without proper treatment, the infection will progress to the latent and possibly tertiary stages.

Latent Syphilis

If syphilis goes untreated it moves from the secondary stage to the latent or hidden stage, where there are no symptoms. This stage can last for years, and the signs and symptoms may never come back, or the disease can progress to the third, or tertiary, stage. (5)

Tertiary Syphilis

Approximately 15 to 30 percent of people infected with syphilis who don’t get treatment will develop late or tertiary syphilis. The symptoms can depend on the complications that occur, but can include the following:

• Gummas (or gummata), which are large sores on the skin or inside the body (6)
• Cardiovascular syphilis, which can affect the heart and blood vessels and lead to aortic aneurysm (dilation of the largest artery in the body due to a weakening of the artery wall) and aortic valve insufficiency (5)
• Neurosyphilis, which can cause severe headaches, difficult muscle movements, paralysis, numbness, and dementia (4)

Learn More About Signs and Symptoms of Syphilis

Syphilis is caused by a type of bacteria called Treponema pallidum, which enters the body through minor cuts or abrasions in the skin or mucous membranes, usually during sexual activity.

The infection is contagious both during its primary stage — when the sore first appears — and in its secondary stage, when a rash may develop on the torso, palms of the hands, soles of the feet, or elsewhere on the body.

Syphilis sores also facilitate the transmission of human immunodeficiency virus (HIV), the virus that causes AIDS. This is likely due to the fact that a syphilis sore can bleed, providing an easy way for HIV to enter the bloodstream.

Syphilis may continue to be contagious in the early latent stage, when there are no symptoms.

You cannot get syphilis from using the same clothing, toilet, toilet seat, or utensils as an infected person. You also can’t get it from doorknobs, bathtubs, swimming pools, or other similar facilities.

In rare instances, it can spread through direct, close contact with an active lesion — for example, during kissing. (5)

Although there are signs and symptoms that often come with syphilis, it is possible to have the disease and not know it. Testing is recommended for people who have had unprotected sex or sex with someone who has syphilis. It’s also recommended that people who are sexually active be tested for sexually transmitted infections (STIs) about once a year. (7)

Syphilis testing is usually done by a simple blood draw. If there are open sores, a sample of fluid from the sore may be swabbed and tested. (1)

Prognosis of Syphilis

If syphilis is treated properly with antibiotics, early syphilis can be cured without causing any permanent damage. Antibiotics are also effective in treating later stages of the disease, but any damage to organs that has already occurred won’t be improved. Without treatment, if a person develops tertiary syphilis, there is a risk for severe organ damage or even death. (8)

Syphilis can be cured with treatment and go away. If it goes untreated, syphilis is a lifelong disease.

If it’s diagnosed in its early stages, syphilis can be easily cured with antibiotics.

Medication Options

The drug of choice is the type of penicillin known as penicillin G benzathine (Bicillin L-A).

For people who are allergic to penicillin, some other antibiotics, such as doxycycline (Vibramycin) or ceftriaxone (Rocephin), can be used. But penicillin is the only recommended treatment for pregnant women with syphilis.

Once it’s cured, syphilis doesn’t come back on its own, but you can still get it again if you have contact with someone who has an active syphilis infection.

Alternative and Complementary Therapies

There are no home remedies or alternative therapies to cure syphilis. (8) The good news is, it’s easy to treat in early stages and can often be cured with just one injection of antibiotic.

Learn More About Treatment for Syphilis: Medication and Partner Notification

Prevention of Syphilis

There is no vaccine for syphilis.

The only way to completely avoid getting syphilis is to not have sex or engage in intimate physical contact. If that’s not practical or desirable, the following can help reduce your risk:

• Having only one sexual partner (and ensuring that that person is monogamous, too)
• Using condoms during sexual activity
• Avoiding alcohol and recreational drugs (which can compromise your judgment, leading to unsafe sexual practices)

In addition, it’s recommended that all pregnant women be screened for syphilis and, if they have it, be treated with penicillin to prevent congenital syphilis in their offspring.

If syphilis is not treated, it can affect your heart, brain, and eyes and may be life-threatening.

Research has linked the infection to aneurysms and inflammation of the aorta, the major artery in your body. (9) The infection can also damage heart valves.

Complications of syphilis may also include such cardiovascular and neurological problems as:

• Stroke
• Meningitis
• Hearing impairment
• Dementia or memory loss

Ocular syphilis is when the infection spreads to the eye. This can cause vision changes or even blindness. (8)

Learn More About the Complications of Syphilis: How It Affects Your Body in the Short and Long Term

Syphilis Transmission From Mother to Child (Congenital Syphilis)

When syphilis is passed from an infected mother to her baby during pregnancy or childbirth, it’s called congenital syphilis, and it is a severe, potentially life-threatening condition for the baby.

Nearly one-half of all children infected with syphilis while in the uterus die shortly before or after birth. (10)

The disease is also associated with blindness, deafness, physical deformities, and damage to the baby’s nervous system.

In an infant born with congenital syphilis, the risk of complications can be reduced by early detection and treatment with penicillin.

Congenital syphilis can be prevented by treating the mother for syphilis during pregnancy.

The CDC recommends testing all pregnant women for syphilis at their first prenatal visit and retesting women early in their third trimester and at delivery if they are at high risk of having acquired syphilis during their pregnancy. (11)

Learn More About the Dangers of Syphilis During Pregnancy

There were more almost 134,000 reported new diagnoses of syphilis (all stages) in the United States in 2020 — a 52 percent increase from 2016. (4)

A large percentage of cases occurred among gay, bisexual, and other men who have sex with men (MSM). But rates of primary and secondary syphilis have also been increasing in heterosexual men and women and in all age groups.

While people ages 15 to 44 accounted for nearly 81 percent of primary and secondary syphilis cases in 2018, rates increased by 21 percent among people ages 55 to 64 and by nearly 29 percent among those age 65 and older. (12)

These numbers serve as a reminder that older Americans, baby boomers included, still need to protect themselves during sex, particularly when initiating a new sexual relationship.

There is a higher rate of primary and secondary syphilis among certain Black, Indigenous, and People of Color (BIPOC) populations than among white Americans.

Black Americans and Syphilis

Black Americans have 4.7 times the rate of primary and secondary syphilis compared with white Americans; in 2018, the rate of reported syphilis among Black Americans was 28.1 cases per 100,000 people, while among white Americans it was 6 cases per 100,000 people. (12)

Congenital syphilis rates in 2018 were 6.4 times higher among infants born to Black mothers (86.6 cases per 100,000 live births) compared with white mothers (13.5 cases per 100,000 live births).

Black men have the highest rate of syphilis — 49.5 cases per 100,000 population — of any of the racial and ethnic groups tracked by the CDC. That statistic is especially concerning in light of the “Tuskegee Study of Untreated Syphilis in the Negro Male,” one of the most infamous studies in American health research and low point in clinical studies. Initiated in 1932, the 40-year study was conducted by Public Health Service officials and followed 600 rural Black men in Alabama, about two-thirds of whom had syphilis. The men were never told their diagnosis and were denied treatment for the disease (penicillin became available as a treatment for syphilis in 1943).

The unethical study was ended when whistleblowers revealed what the researchers were doing. Many men in the study died from complications due to syphilis, and many of the wives and children of the men contracted the disease. (13)

There is research to indicate that the damage goes far beyond what was inflicted on the men and their families who were directly involved in the study and that the Tuskegee Study played a major role in the reduced life expectancy of Black men that exists today. One legacy of the experiment is a lack of trust many Black men have toward the U.S. medical system, which is one reason Black men are less likely to seek healthcare. (14)

Hispanic Americans and Syphilis

Hispanic Americans also had a higher rate of primary and secondary syphilis compared with white Americans in 2018, with 13 cases per 100,000 people.

Congenital syphilis was similarly more common among Hispanic mothers than white mothers: In 2018, there were 44.7 cases per 100,000 live births, making the rate 3.3 times higher than for white births. (12)

American Indians, Alaska Natives and Syphilis

The 2018 rate of primary and secondary syphilis for American Indians and Alaska Natives was 2.6 times the rate for white Americans, with 15.5 cases per 100,000 people. The rate of congenital syphilis cases was also higher, with 79.2 cases per 100,000 live births. (12)

Syphilis is one of several common sexually transmitted infections, or STIs, also called sexually transmitted diseases (STDs).

Among those is HIV (human immunodeficiency virus), a virus that attacks the body’s immune system. Once a person gets HIV, they have it for life. Having syphilis increases the risk of transmitting, as well as getting infected with, HIV. (15)

History of Syphilis

Syphilis has been afflicting humanity for a long time. The first recorded epidemic swept through Europe in the 15th century, although where it started remains unclear.

At that time, syphilis appears to have been a much more severe illness than it is today, causing horrendous skin lesions and pain, and quickly leading to death.

The treatments, such as they were, were ineffective, often painful, and sometimes killed the patient before the disease did.

By the 18th century, syphilis had become less virulent, more closely resembling the disease it is today.

But it was only in the early 1900s that the cause of syphilis was found, and only in 1943 that the first syphilis patients were cured with penicillin, at the U.S. Marine Hospital in Staten Island, New York.

Learn More About the History of Syphilis

Myths and Facts About Syphilis

Given how long it took to discover the cause of syphilis, it’s not surprising that some mistaken beliefs about it developed over the years. One early belief, for example, was that syphilis is an inherited disease. It is not.

More surprising, perhaps, is that certain myths about syphilis persist today, when so much more is known about it.

One potentially dangerous myth is that you can tell if you have syphilis. Often, you cannot. If the initial, painless sore is hidden in the anus, vulva, or cervix, you may not notice it at all. Similarly, you may or may not notice — or correctly identify — the skin rashes or sores that mark the secondary stage of syphilis. And once they clear up, you may have no symptoms for a long time, but still carry the infection in your body.

Another potentially dangerous myth is that syphilis is a thing of the past. In fact, syphilis rates are on the rise. That’s why every sexually active person should be aware of syphilis, how it’s spread, and how to avoid getting it.

Learn More About Myths and Facts About Syphilis

Many organizations offer information on sexual health and STDs, including syphilis, and some can provide testing and treatment, as well.

GetTested

This CDC site can help you find an STD testing location near you.

American Sexual Health Association

This nonprofit organization operates from the premise that everyone has the right to information and services that will help them be sexually healthy. They aim to provide resources along with information that is reliable, science-based, and stigma-free.

Be in the Know

This United Kingdom–based charity provides information and education on HIV, AIDS, and other sexually transmitted diseases to a global audience. The website additionally has information on puberty, sexuality, and safer sexual practices.

Planned Parenthood

This nonprofit organization provides care, education, and advocacy for reproductive health and sexual health.

Learn More About Sexual Health Resources

Additional reporting by Becky Upham.