Syphilis is a bacterial infection that is usually caught by having sex with someone who is infected.

The bacteria that cause syphilis are called Treponema pallidum. They can enter your body if you have close contact with an infected sore, normally during vaginal, anal or oral sex, or by sharing sex toys with someone who is infected.

Pregnant women can pass the condition on to their unborn baby, which can cause stillbirth or the death of the baby shortly after labour.

It may also be possible to catch syphilis if you are an injecting drug user and you share a needle with somebody who is infected.

It is extremely rare for syphilis to be spread through blood transfusions, as all blood transfusions in the UK are tested for syphilis.

Syphilis also cannot be spread by using the same toilet, clothing, cutlery or bathroom as an infected person, as the bacteria cannot survive for long outside the human body.

Three stages of disease

The symptoms of syphilis develop in three stages, described below.

stage 1 (primary syphilis) – symptoms of syphilis begin with a painless but highly infectious sore on the genitals, or sometimes around the mouth. If somebody else comes into close contact with the sore, typically during sexual contact, they can also become infected. The sore lasts two to six weeks before disappearing.

stage 2 (secondary syphilis) – secondary symptoms, such as a skin rash and sore throat, then develop. These symptoms may disappear within a few weeks, after which you experience a latent (hidden) phase with no symptoms, which can last for years. After this, syphilis can progress to its third, most dangerous stage.

stage 3 (tertiary syphilis) – around a third of people who are not treated for syphilis will develop tertiary syphilis. At this stage, it can cause serious damage to the body.

The primary and secondary stages are when you are most infectious to other people. In the latent phase (and usually around two years after becoming infected), syphilis cannot be passed on to others.

Tertiary syphilis is rare in the UK.

What to do

If you suspect you have syphilis, visit a genitourinary medicine (GUM) clinic, sexual health clinic or your GP as soon as possible.

The earlier syphilis is treated, the less chance there is of serious complications. Find your nearest sexual health clinic by searching by town or postcode.

How common is it?

The number of diagnoses of syphilis has risen substantially in the UK in the past decade. There have been several local outbreaks across England, the largest of which was in London between 2001 and 2004. Rates are highest among men who have sex with men.

However, syphilis is still one of the less common sexually transmitted infections in the UK. Between 2011 and 2012, there were 2,978 cases of syphilis diagnosed in the UK.

Treating syphilis

If diagnosed early, syphilis can be easily treated with antibiotics, usually penicillin injections.  

However, if it is not treated, syphilis can progress to a more dangerous form of the disease and cause serious conditions such as stroke, paralysis, blindness, and even death.


It is estimated that people with syphilis are three to five times more likely to catch HIV. This is because the genital sores caused by syphilis can bleed easily, making it easier for the HIV virus to enter the blood during sexual activity.

Infection with both HIV and syphilis can be serious because syphilis can progress much more rapidly than normal.

Preventing syphilis

The only guaranteed way to prevent a syphilis infection is to avoid sexual contact or to only have sexual contact with a faithful partner who has been tested and does not have the infection.

You can reduce your risk of catching syphilis and other sexually transmitted infections (STIs) by:

using a male condom or female condom during vaginal, oral and anal sex

using a dental dam (a square of plastic) during oral sex

avoiding sharing sex toys


Symptoms of syphilis 

The symptoms of syphilis are the same for men and women, and can be difficult to recognise. They are often mild, which means you can pass on the infection without knowing you have it.

The symptoms develop in three stages:

primary syphilis

secondary syphilis

tertiary syphilis

Primary syphilis

The initial symptoms of syphilis can appear any time from 10 days to three months after you have been exposed to the infection.

The most common symptom is the appearance of a small, painless sore or ulcer called a chancre. The sore will appear on the part of your body where the infection was transmitted, typically the penis, vagina, or around the anus.

The sores can also appear in the mouth or on the lips, tonsils, fingers or buttocks. Most people only have one sore, but some people have more.

You may also experience swelling in your lymph glands (small organs found throughout the body, such as in the neck, groin or armpit).

The sore is painless and may be overlooked, so the condition can be spread without you realising you have an infection.

The sore will then disappear within two to six weeks. If the condition is not treated, syphilis will move into its second stage.

Secondary syphilis

The symptoms of secondary syphilis will begin a few weeks after the disappearance of the sore.

Symptoms can include:

a non-itchy skin rash appearing anywhere on the body, but commonly on the palms of the hands or soles of the feet

small skin growths, often mistaken for genital warts – on women these appear on the vulva and for both men and women they appear around the anus

flu-like symptoms – such as tiredness, headaches, joint pains and fever

swollen lymph glands

weight loss

patchy hair loss

These symptoms may disappear within a few weeks, or come and go over a period of months.

Latent phase

Without treatment, syphilis will then move into its latent (hidden) phase, where you will experience no symptoms, even though you remain infected.

Latent syphilis can still be passed on during the first year of this stage of the condition, usually through sexual or close physical contact. However, after a couple of years, you cannot pass the infection to others, even though you remain infected.

The latent stage can continue for many years (even decades) after you first become infected.

Latent syphilis is rare in the UK. However, without treatment, there is a risk that latent syphilis will move on to the third, most dangerous stage – tertiary syphilis.

Tertiary syphilis

The symptoms of tertiary syphilis can begin years or even decades after initial infection. Around a third of people who are not treated for syphilis develop serious symptoms at this stage.

The symptoms of tertiary syphilis will depend on what part of the body the infection spreads to. For example, it may affect the brain, nerves, eyes, heart, bones, skin or blood vessels, potentially causing any of the following symptoms:



loss of co-ordination





heart disease

skin rashes

At this stage, syphilis can be dangerous enough to cause death.


Diagnosing syphilis 

If you suspect you have syphilis, visit a genitourinary medicine (GUM) clinic, sexual health clinic or your GP as soon as possible. The earlier syphilis is treated, the less chance there is of serious complications.

You do not have to pay if you go to a GUM clinic. If you go to your GP surgery, you may have to pay a prescription charge for the treatment.

What happens at a GUM clinic?

Some clinics are walk-in clinics, while you may need to book an appointment at others. Ring first to find out or look on their website.

When you attend a clinic, you will be asked for your name, date of birth and contact details, and you will be registered as a patient. These details are confidential and will not be passed to your GP unless you request them to be.

The clinic doctor or nurse will first ask why you have attended the clinic. You will also be asked for a sexual history, which includes questions such as:

When did you last have sex?

Did you use a condom?

Have you had a sexually transmitted infection (STI) before?

Are you are on any medication?


The doctor or nurse will examine your genitals. For men, this involves looking at the penis, foreskin and urethra (the hole at the end of the penis where urine comes out).

For women, it involves an internal examination of the vagina. Both men and women may also have their anus examined.

They may also check your body for any rashes or growths and examine your mouth and throat.


After the examination, you will have a blood test for syphilis.

If sores are present, a swab (similar to a cotton bud) will be used to take a small sample of fluid from the sore. This is then either looked at under a microscope in the clinic or sent to a laboratory for examination.

You should also be routinely tested for the presence of other STIs, such as HIV, chlamydia and gonorrhoea, as it is possible to have more than one STI at a time.

The results should be available in 7 to 10 days.

Blood test

If you are infected with syphilis, your body produces antibodies (proteins released as part of your immune response) against the syphilis bacteria.

One way to determine whether you have syphilis is to have a sample of your blood tested for the presence of these antibodies.

A positive result (antibodies present) indicates that you either have the infection or you used to have it. This is because the antibodies can remain in your body for years, even after a previous infection was successfully treated.

A negative result does not necessarily mean that you do not have syphilis as the antibodies may not be detectable for up to three months after infection. You may be advised to repeat the test in three months' time.

Every pregnant woman should have a blood test for syphilis as the infection can kill unborn or newborn babies.

The blood test is usually done during an antenatal appointment at weeks 11 to 20 of pregnancy.

If the test is positive, treatment for both the mother and baby can begin.


Treating syphilis 

Primary and secondary syphilis can be successfully treated with a single dose of penicillin, which is given as an injection into your buttock.

You will be prescribed another antibiotic in tablet form if you are allergic to penicillin.

Later stages of the disease need to be treated with three penicillin injections, which are given at weekly intervals.

Treatment usually lasts around two weeks, but can take longer in some cases.

Side effects of antibiotics

Some of the antibiotics used to treat syphilis can interfere with methods of contraception that contain the hormones oestrogen and progestogen, such as the combined pill or contraceptive patch.

Tell your doctor or nurse if you are using these methods of contraception so they can advise you on additional contraceptive methods to prevent you getting pregnant.

Refrain from any kind of sexual activity or close physical contact with another person until your treatment is complete and your sexual partner has been tested and treated.

Jarisch-Herxheimer reaction

A small number of people experience a reaction to the antibiotics, which is known as the Jarisch-Herxheimer reaction. It is thought that the reaction is triggered by the toxins released when a large number of bacteria are killed after antibiotic treatment.

The Jarisch-Herxheimer reaction causes flu-like symptoms such as fever, headaches and muscle and joint pain. These normally only last 24 hours, are nothing to worry about, and cause no serious problems.

The symptoms can be treated with paracetamol, but contact your GP or the genitourinary medicine (GUM) clinic if the symptoms are severe or do not settle down.

Follow-up test

Once the course of antibiotics has finished, you will be asked to return to the GUM clinic so a follow-up blood test can be carried out to check that the infection has gone.

You can still catch syphilis again, even after you have been successfully treated for it.

Tertiary syphilis

Treatment of tertiary syphilis requires longer courses of antibiotics and may need intravenous treatment (administered directly into the vein). While treatment can stop the infection, it cannot repair any damage that has already been caused by the tertiary syphilis.

Telling your partner

If you have syphilis, it is important that your current sexual partner, or any sexual partner you have had since being exposed to infection, is tested and treated.

Some people can feel angry, upset or embarrassed about discussing syphilis with their current partner or former partner. Do not be afraid to discuss your concerns with the clinic staff or your GP. They can advise you about who should be contacted and the best way to contact them.

The clinic can give you a "contact slip" to give to your partner or partners. This slip explains to that person that they may have been exposed to syphilis and that they should go for a check-up. The slip does not have your name on it and your details will remain totally confidential.

If you would prefer, the clinic can contact your recent partner for you. This is usually done by phone or letter. Again, your details will remain totally confidential and your partners will be given no information about you without your consent.

Nobody can force you to tell any of your partners about your syphilis, but it is strongly recommended. If it is left untested and untreated, syphilis can lead to death.


Syphilis in pregnancy can be successfully treated using antibiotics. There are no risks to your unborn baby from the antibiotics.

It is vitally important that pregnant women receive treatment for syphilis because it can cause serious birth defects, miscarriage or stillbirth if it is left untreated.

Avoiding sex

Do not have vaginal, anal or oral sex and avoid any kind of skin contact with your partner until you have finished treatment.

Otherwise, you could be infected again or you could pass the infection on to someone else.


Preventing syphilis 

The only guaranteed way to prevent a syphilis infection is to avoid sexual contact or to only have sexual contact with a faithful partner who has been tested and is not infected.

Male condoms and female condoms can reduce your risk of catching syphilis, but cannot prevent it altogether. You can still catch syphilis if your mouth makes contact with a sore on an infected person's anus or vagina, for example.

It is important to not only use a condom during vaginal, oral and anal sex, but also consider using a dental dam (a square of soft plastic) when your mouth makes contact with your partner's vagina or anus. This will reduce your risk of any sexually transmitted infection (STI), not just syphilis.

Avoid sharing sex toys. If you do share them, wash them or cover them with a condom before each use.

Sexual penetration or ejaculation does not need to take place for syphilis to spread.

If you are an injecting drug user, do not use other people's needles. Many pharmacies and local authorities offer needle exchange programmes, where used needles can be exchanged for clean ones. Your GP or drug counsellor should be able to provide more information.