Syphilis is caused by the bacteria Treponema pallidum and is transmitted through sexual contact. It can be hard to diagnose, but without treatment, it can cause serious damage to multiple body systems over time.

People have been getting, treating, and surviving syphilis for hundreds of years. In fact, treatments are so well established that, at one point, it was thought possible to eradicate syphilis completely. Despite this, rates of syphilis are actually rising among several demographics in the United States.

In 2020, 133,945 new cases of syphilis (all stages) were reported in the United States, according to the Centers for Disease Control and Prevention (CDC). Syphilis in people with vaginas is rising slightly more than in people with penises, though both groups are seeing an uptick in cases overall.

Someone can have it without showing any symptoms for years. However, the earlier syphilis is discovered, the better. Syphilis that remains untreated for a long time can cause major damage to important organs, such as the heart and the brain.

Understanding the symptoms and causes of syphilis can help you protect yourself. If you do have syphilis, understanding this infection can help you recognize signs of the condition and prevent transmission.

Let’s go over what we know about syphilis, who is most at risk, and what the standard treatments for it are today.

Syphilis is caused by a bacterial infection. In 1905, German scientists discovered that the bacterium Treponema pallidum is responsible for the infection.

The only way syphilis is transmitted is through direct contact with syphilitic chancres, or sores. These sores tend to develop on or in the:

  • mouth
  • penis
  • vagina
  • anus

Syphilis is primarily transmitted sexually. That means you can contract it through oral, anal, or vaginal sex, or direct genital-to-genital contact.

Babies can contract syphilis if their mother has an untreated infection. This is called congenital syphilis. Syphilis can also be transmitted through blood transfusions, although that is extraordinarily rare.

Contrary to myth, you cannot contract syphilis by:

  • sharing a toilet
  • wearing another person’s clothing
  • using another person’s eating utensils

This is because the bacteria that cause syphilis can’t live for very long outside the human body.

Anyone can contract syphilis. However, certain factors may increase your chances of contracting an infection. The following groups of people have an increased risk of contracting syphilis:

  • people who have sex without a barrier method, like a condom, with multiple partners
  • men who have sex with men
  • people who have HIV
  • people who have partners with syphilis

The four stages of syphilis are:

Syphilis is most infectious during the first two stages.

When syphilis is in the hidden, or latent, stage, the disease remains active but often doesn’t cause symptoms. Tertiary syphilis is the most destructive to health.

Primary syphilis

The primary stage of syphilis occurs about 3 to 4 weeks after a person contracts the bacteria. It begins with a small, round sore called a chancre. A chancre is painless, but it’s highly infectious. People may not even notice when they have one. This sore may appear wherever the bacteria entered the body, such as on or inside the mouth, genitals, or rectum.

On average, the sore shows up around 3 weeks after infection, but it can take between 10 to 90 days to appear. The sore remains for 2 to 6 weeks. Sometimes the only symptom will be swollen lymph nodes.

Syphilis is transmitted by direct contact with a sore. This usually occurs during sexual activity, including oral sex.

Secondary syphilis

Skin rashes and a sore throat may develop during the second stage of syphilis. The rash won’t itch and is usually found on the palms and soles, but it may occur anywhere on the body. Some people don’t notice the rash before it goes away.

Other symptoms of secondary syphilis may include:

These symptoms will go away whether treatment is received. However, without treatment, a person still has syphilis.

Secondary syphilis is often mistaken for other conditions, such as:

For this reason, syphilis has been known as the “great imitator.” Because the symptoms can be so nonspecific, people experiencing symptoms may ignore them, or sometimes clinicians don’t suspect the presence of the infection.

Latent syphilis

The third stage of syphilis is the latent, or hidden, stage. The primary and secondary symptoms disappear, and there won’t be any noticeable symptoms at this stage. However, the bacteria remain in the body. This stage could last for years before progressing to tertiary syphilis.

Tertiary syphilis

The last stage of infection is tertiary syphilis. About 14 to 40 percent of people with syphilis enter this stage. Tertiary syphilis can occur years or decades after the initial infection. Tertiary syphilis can be life-threatening. Some other potential outcomes of tertiary syphilis include:

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If you think you might have syphilis, go to your doctor as soon as possible. If you prefer, you can also use a local health clinic for testing.

Your doctor or healthcare professional will take a blood sample to run tests, and also conduct a thorough physical examination. If a sore is present, they may take a sample from the sore to determine if the syphilis bacteria are present.

If your doctor or healthcare professional suspects that you’re having nervous system problems because of tertiary syphilis (and you have positive screening blood tests), you may need a lumbar puncture, or spinal tap. During this procedure, spinal fluid is collected so that your doctor can test for syphilis bacteria.

If you’re pregnant, your doctor should screen you for syphilis and other sexually transmitted infections (STIs) as part of your regular prenatal care during the first trimester. This is because STIs can increase the risk of pregnancy complications, such as miscarriage, stillbirth, and premature birth.

Doctors also do an STI screening that includes syphilis because it can be transmitted to the fetus. This is known as congenital syphilis. Untreated congenital syphilis can cause severe damage in a newborn and be life threatening.

A pregnant person will almost always transmit syphilis to their baby. This is why treatment for syphilis is important during pregnancy to protect your health as well as the health of your baby.

Babies born with congenital syphilis may develop:

Untreated congenital syphilis can lead to late-stage syphilis. This can cause damage to a baby’s:

  • bones
  • teeth
  • eyes
  • ears
  • brain

Penicillin is the main treatment for syphilis during pregnancy. If you have a penicillin allergy, your doctor can still administer penicillin over the course of several hours. This allows your body to receive the drug without having an allergic reaction.

Testing for syphilis at home

You can test for syphilis with an at-home testing kit. Any result, either positive or negative, should be followed up with a doctor’s appointment.

There are several at-home syphilis tests on the market. If you have an increased risk of contracting syphilis for any reason, testing regularly at home may be beneficial.

Syphilis testing is also readily accessible through routine clinic appointments or at most city health departments. These tests are often available at little to no cost. Healthline has a state-by-state resource here that can help.

Primary and secondary syphilis are easy to treat with a penicillin injection. Penicillin is one of the most widely used antibiotics and is usually effective in treating syphilis. People who are allergic to penicillin will likely be treated with a different antibiotic, such as:

If you have neurosyphilis, you’ll get daily doses of penicillin intravenously. This will often require a brief hospital stay. The damage caused by late syphilis can’t be reversed. The bacteria can be killed, but treatment will most likely focus on easing pain and discomfort.

During treatment, make sure to avoid sexual contact until all sores on your body are healed and your doctor tells you it’s safe to resume sex. If you’re sexually active, your partner should be treated as well. Don’t resume sexual activity until you and your partner have completed treatment.

If you need help finding a primary care doctor, then check out our FindCare tool here.

The Jarisch-Herxheimer reaction (JHR) is a common, short-term side effect of syphilis treatment. Fewer than 30 percent of people with primary or secondary syphilis may experience JHR symptoms within 24 hours of treatment.

JHR is an immune system reaction. It causes temporary symptoms that range from very mild to more severe, including:

  • fever
  • chills
  • skin rash
  • gastrointestinal symptoms, such as nausea and vomiting
  • headache
  • joint or muscle pain

JHR symptoms usually dissipate within several hours.

The best way to prevent syphilis is to practice safe sex. Use condoms during any type of sexual contact. In addition, it may be helpful to:

  • Use a dental dam (a square piece of latex) or condoms during oral sex.
  • Avoid sharing sex toys.
  • Get screened for STIs and talk with your partners about their results.

Syphilis can also be transmitted through shared needles. Avoid sharing needles if using injected drugs.

Untreated syphilis can have devastating effects, including:

  • gummas, which contain masses of dead, swollen, fiber-like tissue. They’re most often found in the liver. They can also occur in the brain, heart, skin, bones, eyes, and testis.
  • blindness
  • hearing loss
  • brain damage
  • paralysis
  • meningitis
  • heart valve damage
  • aneurysm
  • aortitis (inflammatory aortic disease)

HIV

People with syphilis have a significantly increased chance of contracting HIV. The sores the disease causes make it easier for HIV to enter the body.

It’s also important to note that those with HIV may experience different syphilis symptoms than those who don’t have HIV. If you have HIV, talk with your doctor about how to recognize syphilis symptoms.

The first stage of syphilis can easily go undetected. The symptoms in the second stage are also common symptoms of other illnesses. This means that if any of the following applies to you, consider getting tested for syphilis. It doesn’t matter if you’ve ever had any symptoms. Get tested if you:

  • have had unprotected (condomless) sex with someone who might have had syphilis
  • are pregnant
  • are a sex worker
  • are in prison
  • have had condomless sex with multiple people
  • have a partner who has had condomless sex with multiple people
  • are a man who has sex with men

If the test comes back positive, it’s important to complete the full treatment. Make sure to finish the full course of antibiotics, even if symptoms disappear. Also avoid all sexual activity until your doctor tells you that it’s safe. Consider getting tested for HIV as well.

People who have tested positive for syphilis should notify all of their recent sexual partners so that they can also get tested and receive treatment.

If you believe there’s a chance you’ve been in contact with syphilis, visit a doctor. The signs and symptoms of syphilis may be difficult, or impossible, to detect without a blood test.

Talk with a doctor if you:

  • notice what you think could be syphilis sores
  • have been told by a sexual partner that they have syphilis
  • are sexually active but have never had an STI test

Also be aware that all pregnant people should receive a syphilis test in their prenatal appointments as part of standard care. If it doesn’t look like this test will be included in your initial prenatal blood panel, ask for it.

Is syphilis 100 percent curable?

Yes. Syphilis can be cured by taking the antibiotics your doctor administers. However, any damage that has already been done by this disease cannot be undone by taking antibiotics.

What are the signs of syphilis in a person with a penis?

The early symptoms of syphilis often go overlooked. A syphilis sore called a chancre usually occurs where the infection enters the body. This can be the penis, scrotum, anus, or mouth. The sore is usually painless and resolves on its own. As the disease progresses, rashes will occur on parts of the body including the palms of the hands and soles of the feet.

How long can you have syphilis without knowing it?

Untreated syphilis progresses into the latency (hidden) stage after the second stage rash resolves. During this stage you’ll have no symptoms. Latency can last anywhere from 1 to 20 years, or longer. If you suspect you may have contracted syphilis years ago, see your doctor for a blood test. You can still have treatment that cures the disease and stops future damage from occurring.

Will I always test positive for syphilis?

You may. The antibodies produced by syphilis may stay in your body, even after treatment has occurred. This means that you may always test positive for this disease, even if you no longer have the bacteria.

Can syphilis be cured?

Yes, syphilis can be cured. The bacterial infection can be resolved by undergoing a full treatment regimen of prescription antibiotics. Any damage done to your body’s organs cannot be reversed by treatment, but further damage will be prevented.