Syphilis

Key points about syphilis

  • Syphilis is a sexually transmitted infection (STI) caused by bacteria.
  • Many people don't get any symptoms and wouldn't know they had it without having a blood test.
  • Treatment is normally with injections of an antibiotic called penicillin.
  • If left untreated, the syphilis bacteria eventually cause damage to your internal organs.
  • Untreated syphilis in pregnancy causes serious problems for babies.
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Syphilis is a sexually transmitted infection (STI) caused by bacteria. It’s 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 infection in the baby which can lead to miscarriage or stillbirth if the mother isn't 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.

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're 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 to 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 1 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 isn't treated in the primary or secondary stages, the symptoms will disappear but you can remain infectious for up to 2 years. 

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.

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. Secondary and tertiary syphilis infections can only be picked up on blood tests. 

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's recommended that every pregnant person has a blood test for syphilis during pregnancy and this is done as part of routine antenatal blood tests early in pregnancy. It's important to continue to test for syphilis later in pregnancy (28 to 32 weeks and at birth) if there is a risk of infection during pregnancy.  

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 when they or their partner has a sexually transmitted infection (STI). However, STIs are not uncommon and there's no need to feel embarrassed. Don't let your feelings stop you from getting medical help or telling your partner. Anyone who is sexually active can get an STI. If you need some help knowing what to say to your partner, Burnett Foundation Aotearoa has a message generator tool(external link) you might find helpful.
  • 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. 

You will need injections of an antibiotic called benzathine penicillin. If you're 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 (eg, 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. 

You shouldn't 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 healthcare provider about this. This is the only way to control the disease and protect the health of sexual partners.

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.

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. 

Rising congenital syphilis in Aotearoa New Zealand needs a strong response(external link) Public Health Communication Centre, NZ, 2023

Clinical guidelines

Syphilis checks  routine for all STI checks and pregnancy (Goodfellow Gem)

There is a concern in New Zealand about the number of cases of congenital syphilis, and that testing in pregnancy is not routine. There is also a low incidence of testing as part of routine sexual health checks.

Continuing professional development

Podcasts

Syphilis in pregnant women and congenital syphilis – Dr Massimo Giola(external link) Goodfellow Unit, NZ, 2018
Syphilis in NZ – Dr Massimo Giola(external link) Goodfellow Unit, NZ, 2018

Brochures

 

Syphilis factsheet Health New Zealand | Te Whatu Ora, NZ, 2020

what is syphilis

He aha ia te pākewakewa? What is Syphilis?

HealthEd, NZ, 2023

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Credits: Healthify editorial team. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Cameron Leakey, Research Officer, Burnett Foundation Aotearoa

Last reviewed: