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What is syphilis?

Syphilis is a sexually transmitted infection (STI) caused by a type of bacteria. If it's not treated by a doctor, it can get worse over time and cause serious health problems.

The infection can be active at times and not active at other times. When the infection is active, you have symptoms. When it's not active, you don't have symptoms. But you still have syphilis.

You can get syphilis without having sexual intercourse. Just being in close contact with an infected person's genitals, mouth, or rectum is enough to expose you to the infection. And it can also spread to the fetus of a person who has syphilis during pregnancy.

What causes it?

Syphilis is caused by a type of bacteria. The bacteria are usually spread through sexual contact. They most often enter the body through the tissues that line the throat, nose, rectum, penis, or vagina.

What are the symptoms?

One of the first signs of syphilis is an open sore that appears wherever the bacteria entered the body. As syphilis spreads, a person may get a skin rash and have other symptoms like a fever, swollen lymph nodes, and weight loss. Without treatment, syphilis may cause blindness and nerve and heart problems.

How is it diagnosed?

Your doctor will do a physical exam and ask about your symptoms and sexual history. You'll probably have one or more blood tests, especially if you don't have sores. If you do have sores, your doctor may take a sample of fluid from a sore for testing.

How is syphilis treated?

At any stage of infection, antibiotics work well to cure syphilis. They can't undo the damage already caused by late-stage syphilis. But they can help you avoid further problems from the infection. You and any sex partners that you may have exposed to the infection will need to be treated.

How can you prevent sexually transmitted infections (STIs)?

Here are some ways to help prevent STIs.

  • Limit your sex partners. Sex with one partner who has sex only with you can reduce your risk of getting an STI.
  • Talk with your partner or partners about STIs before you have sex. Find out if they are at risk for an STI. Remember that it's possible to have an STI and not know it.
  • Wait to have sex with new partners until you've each been tested.
  • Don't have sex if you have symptoms of an infection or if you are being treated for an STI.
  • Use a condom every time you have sex. Condoms are the only form of birth control that also helps prevent STIs.
  • Don't share sex toys. But if you do share them, use a condom and clean the sex toys between each use.

Vaccines are available for some STIs, such as HPV. Ask your doctor for more information.

How It Spreads

An infected person who has a sore or a rash can pass syphilis to others. It's usually spread during vaginal, anal, and oral sex. But it can be spread by any close contact with the genitals, mouth, or rectum of an infected person. If you're infected while you're pregnant, you can pass syphilis to your baby.

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Syphilis develops in four stages. Each stage has a different set of symptoms.

One of the first signs of syphilis is a painless open sore called a chancre. Chancres are often found in the mouth, the anus, or the genital area. As syphilis spreads throughout the body, a person may get a skin rash and have other symptoms like a fever, swollen lymph nodes, and weight loss.

You may not notice symptoms of syphilis. Sometimes they're the same as symptoms for other infections. This can cause someone with the infection to put off seeing a doctor. But even if you don't have symptoms, getting tested can confirm if you have syphilis.

If syphilis isn't found and treated in the early stages, it can cause other serious health problems. These can include blindness, problems with the nervous system and the heart, and mental disorders. It can also cause death.

What Happens

The main symptom of the first stage of syphilis is usually an open sore. A rash and other symptoms often occur during the second stage. That's usually followed by a time without symptoms. Syphilis can move to the late stage, causing problems. Antibiotics can't undo damage, but they can cure syphilis at any stage.

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When to Call a Doctor

Call to make an appointment if you:

  • Have sores, bumps, rashes, blisters, or warts on or around the genital or anal area or on any area of the body where you think they could be caused by a sexually transmitted infection (STI).
  • Think you have been exposed to a STI.

Do not have sexual intercourse or other sexual contact until you have been treated by a doctor. If you are diagnosed with syphilis, your sex partner(s) will need to be treated also.

In most areas, public health units or sexual health clinics are able to diagnose and provide assessment and treatment of early syphilis and other STIs.

Watchful waiting

Watchful waiting is a wait-and-see approach. It's not a good choice if you think you were exposed to or have syphilis or another STI. Any symptoms or other changes that suggest syphilis or another STI should be checked by a doctor.

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Examinations and Tests

Your doctor will do a physical exam. You'll be asked about your symptoms and your sexual history.

Syphilis is most often diagnosed with blood tests. A lumbar puncture (spinal tap) may be done if your symptoms suggest the syphilis infection has moved to the brain, spinal cord, or eyes. If you do have sores, your doctor may take a sample of fluid from a sore for testing.

More testing should be done to look for other sexually transmitted infections, such as:

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Treatment Overview

Syphilis can be cured with antibiotics. Penicillin is the preferred medicine. You will need to be treated, and so will any sex partners that may have been exposed to the infection.

At any stage of the infection, antibiotics work well to cure syphilis. They can't undo the damage already caused by syphilis. But they can help you avoid further problems from the infection.

You cannot treat syphilis on your own. It must be treated with medicine that only a doctor can give you. Treatment helps you avoid other serious health problems. And it keeps you from spreading syphilis to others.

Being treated during pregnancy can help you avoid miscarriage or stillbirth. It can also help keep your baby from being born with syphilis.

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  • Get all the recommended shots. Your doctor probably gave you an antibiotic shot. If you've had syphilis for a while, you may need 2 more shots.
  • If your doctor prescribed antibiotic pills, take them as directed. Do not stop taking them just because you feel better. You need to take the full course of antibiotics.
  • Don't have sexual contact with anyone while you're being treated. Wait at least 7 days after you and your partner or partners are treated and until all sores are healed before you have sexual contact. Even if you use a condom, you and your partner or partners can still spread the infection.
  • Wash your hands if you touch an infected area. This helps prevent spreading the infection to other parts of your body or to other people.
  • Tell your sex partner or partners that you have syphilis. They'll need treatment even if they don't have symptoms.
  • Go to all follow-up tests. This helps your doctor check that treatment worked. Your doctor will tell you when to have testing done.

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Current as of: April 19, 2023

Author: Healthwise Staff
Clinical Review Board
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.

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