Syphilis is a sexually transmitted infection that can be treated and cured with antibiotics. If not treated, over time, syphilis can affect the brain, spinal cord and other organs. Having untreated syphilis also increases your risk of catching HIV infection.


In New Zealand, syphilis rates have been increasing, particularly in men who have sex with men (MSM). However, syphilis rates in heterosexual men and women have also been increasing.

Similar trends have also been seen in recent years in Australia, the UK and the US, with increasing syphilis cases first seen in the MSM population, then in the heterosexual population. The increase in syphilis cases in the heterosexual population leads to an increased risk of congenital syphilis.

Syphilis is usually caught through sexual contact with an infected person. However, syphilis can also be spread from an infected mother to the baby during pregnancy.   

Syphilis in pregnancy

If a pregnant woman has syphilis, the unborn baby may be infected. An infected foetus may die in the womb (stillbirth), shortly after birth, or the baby may be born early with or without congenital abnormalities such as blindness, deafness and meningitis caused by the infection. Untreated babies may become developmentally delayed, have seizures or die.

Related websites

New Zealand Sexual Health Society (NZSHS)
NZSHS provide patient information on a variety of STIs.


The symptoms of syphilis depend on the stage of infection; primary, secondary, and late (tertiary).

Primary syphilis

The first sign of syphilis is a sore or ulcer (called a chancre) at the site of infection, usually the genitals, anus or mouth. The sore may be painless and hidden from view so may not be noticed.

The sore usually appears about 3 weeks after infection and can last between 3 and 6 weeks before the sore heals. The sore will heal with or without treatment. However, without treatment the person remains infectious.

Secondary syphilis

Untreated primary syphilis progresses to the secondary stage, symptoms of which most commonly include rashes, often with red or brownish spots on the palms of the hands and soles of the feet. Other symptoms include swollen lymph glands, fever, hair loss, muscle and joint aches, headaches, tiredness, and warty growths in skin folds, especially in the genital or anal areas. 

Symptoms of secondary syphilis can happen while the sore is healing or several weeks after it has healed.

The symptoms of secondary syphilis can last up to 6 months and will disappear without treatment. However, without treatment the person remains infectious and the syphilis infection may progress to the late (tertiary) stage.

Late (tertiary) syphilis

If not treated, a small number of people will get late stage (tertiary) syphilis years after the initial infection. Late syphilis can cause damage to the heart, brain, nerves, eye, blood vessels, liver, bones and joints.

People with late syphilis are not infectious to sexual contacts.


A simple blood test is used to diagnose syphilis. The blood test may not pick up the early stages of infection and repeat tests may be necessary.


Syphilis is usually treated with antibiotic injections. The length of treatment will vary depending on the stage of infection. 

Follow-up blood tests will be required to check that the treatment has been successful.

It is possible to get re-infected with syphilis again in the future, through sexual contact with someone who has syphilis.


The spread of syphilis can be prevented by:

  • practising safer sex including using a condom or oral dam – go to Safer sex and condoms find out more
  • avoiding sex with someone who has a visible ulcer or sore on their genitals
  • limiting the number of sexual partners to reduce the risk of having sex with someone who has syphilis
  • having regular STI check ups for timely diagnosis and treatment
  • informing sexual partners if you are diagnosed with syphilis so that they can also be tested and treated.

Syphilis is one of the routine blood tests for pregnant women in New Zealand. Treatment of syphilis early in pregnancy is very effective in preventing syphilis in the unborn baby.

For more advice on safe sex, STI checks and where to get them, and answers to frequently asked questions, go to Just the Facts about Sexual Health and STIs.

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