Patient information from BMJ

Syphilis: what is it?

Last published:Jan 18, 2021

Syphilis is an infection that can be passed from person to person during sex. Antibiotics work well to cure the infection. But, if it's left untreated, syphilis can spread to other parts of your body and cause serious health problems.

This leaflet gives an overview of the syphilis infection, including its symptoms and stages. To learn more about tests and treatments for syphilis, see our leaflet Syphilis: how is it diagnosed and treated?.

What is syphilis?

Syphilis is an infection caused by a type of bacteria called Treponema pallidum. The bacteria pass from person to person during sex, including anal, oral, and vaginal sex.

You may hear syphilis referred to as a sexually transmitted disease (STD) or sexually transmitted infection (STI).

Syphilis is very common worldwide, with more than 10 million people becoming infected each year.

Many people pass the infection to others without realising they have it. This is because syphilis may not cause any noticeable symptoms early on, when it is most likely to be spread.

A pregnant woman with syphilis can pass the infection to her unborn baby.

What are the symptoms?

Syphilis causes different symptoms depending on how advanced it is (its stage) and where it has spread in the body.

Primary stage

Within weeks of being infected, you may notice a sore (called a chancre) in the area where the bacteria entered your body: for example, on your genitals, rectum, or mouth.

The sore can also develop inside your body: for example, on your cervix if you’re a woman (the cervix is the opening to the womb). The sore is almost always painless.

The sore can develop up to 90 days after a person is infected, but most people get it within 14 to 21 days.

It usually goes away within three to six weeks, and some people never notice they have it. Some people get more than one sore.

The sores of primary syphilis contain the syphilis bacteria. Direct contact with these sores during sex is how many people become infected.

Secondary stage

If primary syphilis is not treated, you may develop symptoms of secondary syphilis around four to eight weeks after getting the sore. The symptoms can include:

• fever

• tiredness

• feeling generally unwell

• muscle or joint pain

• a rash on your hands, feet, torso, or scalp

• sores in your mouth or on your genitals

• a wart-like growth on your genitals

• patches of hair loss on your head.

These symptoms will go away in time, although some of them might come back. You can get syphilis if you have direct contact with the sores of secondary syphilis.

Latent stage

After the symptoms of primary and secondary syphilis disappear, you have what's called latent syphilis. ‘Latent’ means ‘hidden’. During this stage you still have syphilis but it is not causing any signs or symptoms.

You can have latent syphilis for years. You are unlikely to pass on the infection during this stage, but it’s still important to practise safe sex by using condoms.

Late stage

Not everyone with untreated syphilis goes on to get late syphilis (also called tertiary syphilis). But for those who do, it can cause very serious health problems.

In late syphilis, the infection has spread to other parts of your body and is causing damage. This can cause different symptoms, depending on where the infection has spread. For example:

If syphilis has spread to your brain or spinal cord, symptoms can include:

• headaches

• seizures

• memory problems

• difficulty controlling your muscles (ataxia)

• problems with your eyesight or hearing, and

• difficulty controlling your bowels or bladder.

If syphilis has spread to your heart, symptoms can include:

• chest pain (angina)

• shortness of breath

• fatigue, and

• a rapid heartbeat.

Syphilis can also damage your liver, blood vessels, nerves, bones, and joints.

Although these problems usually happen only if you’ve had syphilis for a long time, problems in your brain or spinal cord (called neurosyphilis) can happen at any stage of the infection.

Treatment with antibiotics can cure syphilis at any stage. But any damage already done to your body may be permanent. This is why it’s so important to be diagnosed and treated early.

To learn more, see the leaflet Syphilis: how is it diagnosed and treated?.