Syphilis is a sexually transmitted infection (STI) that can cause serious health problems if you do not treat it. It is easy to cure if you treat it early.
In the past 10 years, the number of syphilis cases reported in Australia has significantly increased.
The symptoms of syphilis depend on the stage of your infection. There are 4 stages of syphilis infection:
Primary syphilis happens between 10 and 90 days after infection. You may get a painless sore or sores in or on your:
The sore is a round area of broken skin. The centre may be weepy (oozing) and have pus coming from it. The sores usually go away by themselves after 2 to 6 weeks.
It can be easy to miss the sores because they are usually painless. They may also be hidden from view in your rectum or on your cervix.
However, even when the sore goes away, you can still pass syphilis on to others.
Secondary syphilis usually happens more than 6 weeks after infection. Symptoms of secondary syphilis include:
Often you may not notice these symptoms. If untreated, the symptoms slowly get better over a period of weeks, but they can come back.
Secondary syphilis can spread easily to sexual partners. It can also spread to an unborn baby if you have syphilis and are pregnant.
There are usually no obvious symptoms of latent syphilis. Infection is only found with blood tests.
If you do not treat syphilis at this stage, it can remain latent for life or turn into tertiary syphilis.
Latent syphilis can also be transmitted to an unborn baby during pregnancy.
Tertiary syphilis develops in about 1 in 3 people with untreated latent syphilis.
The bacteria can damage almost any part of your body including your:
This can happen many years after you were first infected with syphilis.
There are three major forms of tertiary syphilis:
Some people with syphilis have no symptoms. This is why it is important to be tested regularly.
Syphilis is caused by bacteria called Treponema pallidum.
You should see your doctor, visit a family planning clinic (Opens in new tab) or a sexual health clinic if you:
You can get syphilis if you have unprotected skin-to-skin contact during vaginal, anal or oral sex.
Syphilis is very contagious (spreads easily) during the primary and secondary stages when you have a sore or rash.
You can also pass on syphilis to someone else if you are in the early latent phase and do not have any sores.
If you are pregnant, syphilis can pass to your baby through the placenta. This is called congenital syphilis (Opens in new tab).
Syphilis can sometimes spread through contact with blood, for example from a needlestick injury or sharing injecting equipment.
Your risk of getting syphilis through a blood transfusion is very low due to:
In Australia, population groups at higher risk of syphilis include:
Your doctor can diagnose syphilis by:
Blood tests to diagnose syphilis look for antibodies. Your body makes antibodies to fight the syphilis infection. Your blood test results can tell you if you have syphilis now or if you had it in the past. It can take your body some time to develop antibodies. This is why your blood test results can be negative, even if you have recently caught syphilis. If this happens to you, you should have another blood test 2 weeks later.
Sometimes you can also have other STIs at the same time as syphilis. Your doctor may offer to test you for other STIs when testing for syphilis.
Syphilis is a nationally notifiable disease in Australia. This means that government health authorities must be told about all cases of syphilis. This is done so that infections can be tracked. It is important to try to stop outbreaks because syphilis can cause long-term health complications.
If you have syphilis, it is very important that you help with contact tracing. This means telling anyone you have had sex with during the past 12 months. They will need testing and treatment if they have it. This will help stop you from being infected again. It also reduces the spread of syphilis.
Your doctor can help you work out who you need to contact.
If you are worried about telling recent sexual partners that you have syphilis, you can send them an anonymous text message or email through some websites, such as Let Them Know (Opens in new tab).
Syphilis is usually treated with an antibiotic medicine called penicillin, as an injection. If you are allergic to penicillin, there are other treatment options available.
Your sexual partners will also need to be tested and treated.
After treatment with penicillin, you may feel like you have the flu. If you feel unwell, you should rest and drink plenty of fluids. This will soon go away without any extra treatment.
There are other things you should do as part of your treatment:
If you are pregnant, you will be tested for syphilis at:
If you are at high risk of syphilis, you will also be tested again around 6 weeks (Opens in new tab) after your baby is born.
It is important that you are treated for syphilis during pregnancy if you have it. If you do not treat syphilis, you can pass it on to your baby (known as congenital syphilis).
Congenital (present from birth) syphilis may cause these serious complications:
You can safely take treatment for syphilis while pregnant. If you treat your infection early, you can reduce the amount of damage congenital syphilis does to your baby.
Read more about syphilis and pregnancy on Pregnancy, Birth and Baby (Opens in new tab).
Syphilis can cause serious health problems if it is not treated. Complications may include:
Syphilis can be passed to your baby during pregnancy. This can be very serious.
You can prevent syphilis and other STIs by practising safe sex:
Find out how we develop and review our content.
Last reviewed: December 2025
Worried about your health?
Select a symptom, answer some questions, get advice
