Syphilis is a sexually transmitted infection (STI) caused by the bacteria Treponema pallidum. If it’s not treated early, syphilis can progress and ultimately become a serious, life-threatening infection.
In 2023, 209,253 cases of syphilis were reported in the United States, which is the greatest number of cases reported since 1950 and an increase of 1 percent since 2022.
Here, we discuss the symptoms, causes, treatments, and screening recommendations for syphilis.
A person can have syphilis and not see or feel any symptoms. It’s also easy to confuse syphilis with other issues, such as pimples or rashes.
The symptoms of syphilis are different depending on the stage of the disease.
Primary Stage
The most common first sign of syphilis is one firm, round, and painless sore, called a chancre. It develops where the bacteria entered the body. The chancre typically appears within three weeks from the time of exposure, usually in the area of the genitals, rectum, or mouth; it can go unnoticed if it is hidden inside the body. Occasionally, more than one sore develops.
The sore typically lasts three to six weeks with or without treatment. However, even if the sore goes away on its own, treatment is necessary to stop the infection from progressing to the secondary stage.
Secondary Stage
This stage usually begins with a rash on one or more areas of the body. The rash can appear rough or red, or as reddish-brown spots, but it may be faint and not noticeable. Other symptoms of syphilis during the secondary stage include the following:
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, during which there are no symptoms. This stage can last for years. The signs and symptoms may never come back, or the disease can progress to the third, or tertiary, stage.
Tertiary Syphilis
Up to 30 to 40 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) are large sores on the skin or inside the body.
Cardiovascular syphilis can affect the heart and blood vessels and lead to an aortic aneurysm (dilation of the largest artery in the body due to a weakening of the artery wall) and aortic valve insufficiency.
Two forms of neurosyphilis — general paresis and tabes dorsalis —are considered a tertiary form of syphilis, although other forms of neurosyphilis can occur at any stage of infection. General paresis causes cognitive impairment, and tabes dorsalis causes a variety of physical problems, including pain in the arms and legs or abdomen.
Neurosyphilis, Ocular Syphilis, and Otosyphilis
Neurosyphilis, ocular syphilis, and otosyphilis are particularly severe manifestations of syphilis and can be seen during any stage of the disease (primary, secondary, or tertiary).
Neurosyphilis This occurs when syphilis bacteria infect the brain or spinal cord. It may cause no symptoms, but in people with meningeal neurosyphilis, it can cause headache, stiff neck, nausea, and vomiting, and in those with meningovascular neurosyphilis, it additionally causes vertigo and leg muscle weakness.
General paresis is a late-stage type of neurosyphilis that can occur 3 to 30 years after a person is first infected with syphilis. Symptoms of general paresis include personality or mood changes, problems with thinking and judgment, memory and language problems, delusions, and seizures.
Tabes dorsalis is another late-stage type of neurosyphilis that can occur 5 to 50 years after infection. Symptoms of tabes dorsalis include pains in the arms and legs or abdomen, lack of muscle coordination, burning or tingling sensations, bladder control and sexual function problems, vision loss, loss of reflexes, loss of sense of vibration, and walking and balance problems.
Ocular Syphilis Syphilis can affect any part of the eye, but it most commonly affects the uvea, the set of structures behind the sclera, or white of the eye. Common symptoms of ocular syphilis include eye redness, blurry vision, floaters, eye pain, and sensitivity to light. Diagnosing ocular syphilis can be challenging since its appearance is largely the same as eye inflammation resulting from other causes.
Otosyphilis When syphilis infects the inner ear, it’s called otosyphilis. Symptoms can include tinnitus (ringing in the ears), vertigo, and hearing loss, which may affect one or both ears, occur suddenly, and progress rapidly. It can be challenging to diagnose if a person does not also have other symptoms of syphilis.
The bacterium that causes syphilis enters the body through minor cuts or abrasions in the skin via various modes of transmission:
Sexual contact with someone who has syphilis (including vaginal, anal, or oral sex)
Direct contact with syphilis sores, which are usually found on the genitals, anus, lips, or mouth
Mother to child transmission during pregnancy or childbirth (called congenital syphilis)
Sharing needles for IV drug use, though this is rare
You cannot get syphilis from using the same clothing, toilet, toilet seat, or utensils as an infected person. Nor can you get it from doorknobs, bathtubs, or swimming pools.
You're at a higher risk of getting syphilis if any of the following factors apply:
Unprotected sex, especially with new or multiple partners
A man who has sex with men
HIV-positive (syphilis and HIV often occur together)
A history of other STIs, which can increase susceptibility
Sex worker or a partner who does sex work
Drugs that impair judgment, which can increase risky sexual behavior
Sexually active with more than one partner.
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 if you have syphilis is to be tested for it, which usually involves a blood test. If there are open sores, a sample of fluid from the sore may be swabbed and tested.
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 STIs, including syphilis, about once a year.
Prognosis of Syphilis
If syphilis is treated early with antibiotics, it 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 reversed. Without treatment, tertiary syphilis can cause severe organ damage or death.
How long syphilis lasts depends on how early it is caught. If it’s treated, it can be cured. If syphilis remains untreated, it can be a lifelong infection.
The drug of choice for curing syphilis is the antibiotic penicillin G benzathine (Bicillin L-A). A single injection of this antibiotic is typically all that’s needed for primary, secondary, and early latent syphilis. A longer course of treatment may be necessary for late latent (more than a year after the initial infection) and tertiary syphilis.
For people who are allergic to penicillin, other antibiotics, such as doxycycline (Vibramycin) or ceftriaxone (Rocephin), can be used.
Penicillin is the only recommended treatment for pregnant women with syphilis.
Neurosyphilis, ocular syphilis, and otosyphilis are treated with aqueous crystalline penicillin G delivered via IV for 10 to 14 days.
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.
There is no vaccine for syphilis. The only way to completely avoid getting syphilis is to abstain from sex and 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 person is also monogamous
Using condoms during sexual activity
Avoiding alcohol and recreational drugs, which can compromise your judgment, leading to unsafe sexual practices
The Centers for Disease Control and Prevention (CDC) recommends that men who have sex with men be screened at least annually for syphilis; people at higher risk for contracting the disease, such as sex workers, should also be screened regularly. 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 infants.
If syphilis is not treated, it can affect your heart, brain, and eyes and may be life-threatening. Complications of syphilis include the following:
Angina (chest pain)
Aortic aneurysm (bulging of the body's largest artery)
When syphilis is passed from an infected mother to her baby during pregnancy or childbirth, it’s called congenital syphilis. This is a severe, potentially life-threatening condition for the baby.
Nearly half of all children infected with syphilis while in the uterus die shortly before or after birth.
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 a high risk of having acquired syphilis during their pregnancy.
In 2023, 209,253 cases of syphilis (all stages, including congenital syphilis) were reported. This is the greatest number of cases reported since 1950 and an increase of 1 percent since 2022.
A large percentage of cases occurred among men who have sex with men. But rates of primary and secondary syphilis have also been increasing in heterosexual men and women and all age groups. In 2023, men who have sex with men accounted for one-third of all primary and secondary syphilis cases.
These numbers serve as a reminder that older Americans still need to protect themselves during sex, particularly when initiating a new sexual relationship.
Primary and secondary syphilis are more prevalent among Black, Indigenous, and People of Color (BIPOC) than among white Americans.
Black Americans and Syphilis
In 2023, non-Hispanic Black or African American patients accounted for a disproportionately high share of syphilis cases, with a 32 percent prevalence, despite representing only 13 percent of the U.S. population.
That statistic is especially concerning in light of the Tuskegee study, one of the most infamous studies in American health research and a 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.
There is research to indicate that the damage goes far beyond what was inflicted on the men and families 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 that many Black men have toward the U.S. healthcare system, which is one reason that Black men are less likely to seek healthcare.
Hispanic Americans and Syphilis
In 2023, Hispanic individuals had fewer cases of syphilis than Black Americans or American Indian or Alaska Native people. Among Hispanic men, there were 17 cases of syphilis per 100,000 people, and among Hispanic women, 6 cases per 100,000 people.
American Indians, Alaska Natives, and Syphilis
Rates of primary and secondary syphilis and congenital syphilis were highest among American Indian or Alaska Native individuals in 2023, representing 58 cases in 100,000 people.
From 2014 to 2018, the number of reported congenital syphilis cases increased by 500 percent in these groups, 6 times what it was for white Americans.
Syphilis is one of several common STIs, including gonorrhea, chlamydia, and human immunodeficiency virus (HIV), the virus that causes AIDS.
Having syphilis increases the risk of transmitting as well as getting infected with HIV. Syphilis sores facilitate the transmission of HIV, as a sore can bleed, providing an easy way for HIV to enter the bloodstream.
Syphilis has been afflicting humanity for centuries. 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 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 as it is now. In the early 1900s, the cause of syphilis was found, and in 1943, the first people with syphilis were cured with penicillin, at the U.S. Marine Hospital in Staten Island, New York.
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 was that syphilis is an inherited disease. It is not.
More surprising, perhaps, is that certain myths about syphilis persist even 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 not notice or correctly identify the skin rashes or sores that mark the secondary stage of syphilis. 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 spreads, and how to avoid getting it.
Syphilis is a sexually transmitted infection caused by the bacteria Treponema pallidum. There are four stages of syphilis: primary, secondary, latent, and tertiary.
Syphilis can affect almost all areas of the body. If left untreated, the disease can cause severe complications.
When caught in its early stages, syphilis can be effectively treated with penicillin or other antibiotics without causing long-term problems.
Cases of syphilis have been on the rise in the United States in recent years. If you are in a high-risk group, talk to your doctor about getting screened for the disease.
