Syphilis is a sexually transmitted infection (STI) caused by a bug that gets into your body through tiny breaks in your skin, mainly in your genital area or mouth.

On this page, you can find the following information:

Key points about syphilis

  1. Many people don’t get any symptoms and would not know they had syphilis without having a blood test.
  2. You get syphilis by having sexual contact, including oral sex with another person with syphilis.
  3. Condoms help prevent syphilis. Having had syphilis once does not protect you from catching it again. 
  4. Treatment is normally with injections of an antibiotic called penicillin.
  5. If left untreated, the syphilis bacteria eventually causes damage to your internal organs. People without symptoms can still develop these problems later on if not treated.

How do you get syphilis?

Syphilis is very infectious and is usually caught by having close sexual contact with an infected person. This may include vaginal, anal or oral sex or just close skin-to-skin contact. The chances of catching syphilis are lower if you use condoms during sex.

Syphilis can also be spread from mother to baby during pregnancy if the mother is infected. It can cause miscarriage, stillbirth or infection in the baby if the mother is not treated.

Syphilis is highly infectious in the earlier stages, so it’s important to diagnose and treat it as soon as possible to prevent its spread.

What are the symptoms of syphilis?

About 50% of people don’t get any symptoms and would not know they have it without having a blood test. People without symptoms can still get problems later on if they are not treated and can still pass the infection on to their sexual contacts. 

For those who do get symptoms, syphilis is divided into 3 stages: primary, secondary and tertiary.

  • Primary and secondary syphilis are also known as infectious syphilis.
  • Tertiary syphilis is known as non-infectious or late-latent syphilis. 

Primary syphilis

The first sign of syphilis is a sore, usually on your genitals but it may also appear on other parts of your body where there has been sexual contact. The sore may be hidden in your cervix, mouth or anus and because it is usually painless it may go unnoticed.

The sore usually appears 3–4 weeks after infection, but sometimes it takes longer. It disappears without you doing anything within a few weeks. 

  • Even though the sore heals, you still have the syphilis infection and can pass it onto others.
  • Any genital sore must be examined by a doctor, even if it starts to heal and is small and painless. 

Secondary syphilis

Sometimes a rash appears quite suddenly about 6 weeks after infection. It may appear on your body, face, arms and often on the palms and soles of your feet.

The type of rash and how large it is varies from person to person and even on different parts of the body of the same person. It may be very obvious but it may be so mild that you don’t notice it. It rash lasts up to 4–6 weeks and often disappears as suddenly as it appeared. 

There may also be one or more of the following symptoms: 

A person in the primary or secondary stage of syphilis is very infectious because the sores and rashes are full of syphilis bacteria. There is a very high chance of infecting a sexual partner.

If syphilis is not treated in the primary or secondary stages, the symptoms will disappear but you can remain infectious for up to 2 years. 

At this stage, infection is only picked up on blood tests.

Tertiary syphilis

If not treated, a small number of people will get late stage syphilis (or tertiary syphilis), which can cause damage to your heart, brain, nerves, blood vessels, liver, bones and joints many years later.

Treatment is still effective and can prevent further damage, but will not repair any damage that has already taken place. Tertiary syphilis is not infectious and can be avoided by treatment at an earlier stage.

How is syphilis diagnosed?

Syphilis is usually diagnosed by blood tests for antibodies to the syphilis bacterium. It can take up to 3 months to develop antibodies, so the tests may be negative early on. If you have a genital sore or body rash, the doctor may also take samples from the sores to be sent for laboratory analysis. 

Does syphilis affect pregnancy?

Syphilis can be spread from mother to baby during pregnancy if the mother is infected. This can result in stillbirth, miscarriage or an infected baby. An infected baby may be born without symptoms but could develop them within a few weeks and could become very ill. Proper treatment of the mother during pregnancy will prevent the baby being born with syphilis.  

It is recommended that every woman have a blood test for syphilis during pregnancy and this is done as part of routine antenatal blood tests early in pregnancy. It is important to continue to test for syphilis later in pregnancy if there is a risk of infection during pregnancy.  

Do I need to tell sexual partners if I have been diagnosed with syphilis?

If you have been diagnosed with syphilis, all your sexual partners from the past few months must be advised to see their doctor or local sexual health clinic. You doctor will let you know how many months this needs to be. 

  • If you had sex with them while the rash or sore was present they will usually need treatment.
  • You should not have sex until your rash or sore clears up because you remain infectious for some time after treatment. This is the only way to control the disease and protect the health of sexual partners.
  • Anyone who has had sex with an infected person in the past must be tested and treated if necessary.
  • Some people feel embarrassed, scared or angry when they or their partner has a sexually transmitted infection (STI). This is common and okay. Don’t let these feelings stop you from getting medical help or telling your partner. Anyone who is sexually active can get an STI.
  • Talk to partners as soon as possible. If left untreated, syphilis can cause complications and be spread to other partners. Tell current partners or past sexual contacts to see their doctor or sexual health clinic because they may have an STI.
  • If you need help contacting your sexual partner(s), talk to the doctor or nurse at the sexual health clinic for advice. 

How is syphilis treated?

You will need injections of an antibiotic called benzathine penicillin. If you are allergic to penicillin other antibiotics will be used.

  • In most cases penicillin injections are used but under certain circumstances the medication may be taken by mouth (eg, tetracycline or erythromycin tablets).
  • Take the treatment exactly as prescribed and do not miss any doses, as this will reduce its effect.
  • The length of treatment varies according to the stage of infection and type of antibiotic used.
  • Proper treatment of women during pregnancy will prevent the baby being born with syphilis.
  • After treatment with penicillin injections some people (particularly in early syphilis) have a flu-like illness for 24 hours. This includes fevers, aches and pains, and generally feeling unwell. This will go away and doesn’t require any special treatment, except possibly over-the-counter medication (such as paracetamol) for fever and pain, and resting.

After treatment, follow-up blood tests are essential for at least 1 year to ensure the treatment has been successful. If it seems likely that the infection has occurred recently, sexual partners are also usually treated because the blood tests may not become positive for several weeks. Having syphilis once does not protect you from getting it again. 

Should I avoid sex when I have syphilis?

You should not have sex until your rash or sore clears up because you remain infectious for some time after treatment. How long will vary from one person to another, so ask your doctor or nurse about this. This is the only way to control the disease and protect the health of sexual partners.

How is syphilis prevented?

Syphilis can’t always be prevented but if you’re sexually active you can reduce your risk by practising safer sex.

  • Use a male condom or female condom during vaginal, oral and anal sex.
  • Use a dental dam (a square of plastic) during oral sex.
  • Avoid sharing sex toys – if you do share them, wash them and cover them with a condom before each use.

These measures can also reduce your risk of catching other STIs. Because many people don’t have symptoms, having regular sexual health check-ups is important.

Where do I go for a check-up?

Sexual health clinics have specialists who are experienced in diagnosing and treating syphilis. Treatment is free and confidential and the people there can help with testing your sexual partners. 

Learn more

Syphilis Ministry of Health, NZ
Syphilis Just the Facts, NZ
Syphilis patient information The NZ Sexual Health Society
Syphilis Healthy Sex, NZ


  1. Syphilis management summary NZ Sexual Health Society, 2017
  2. Syphilis and pregnant women and congenital syphilis Goodfellow Podcast, NZ
  3. Syphilis in NZ Goodfellow Podcast, NZ

Leave a Reply

Your email address will not be published. Required fields are marked *