Syphilis is a sexually transmitted infection. It can be treated and cured with antibiotics. If it is not treated, over time syphilis can affect the brain, spinal cord and other organs. Having untreated syphilis also increases the risk of getting HIV.
Syphilis is usually transmitted through sexual contact with an infected person. Syphilis can also be spread from an infected mother to the baby during pregnancy.
In New Zealand, syphilis rates have been increasing since 2012, particularly in men who have sex with men (MSM). 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. The increase in syphilis cases in the heterosexual population has led to an increased risk of congenital syphilis. Congenital syphilis occurs when a pregnant person who is infected with syphilis spreads the disease to the fetus through the placenta.
Syphilis in pregnancy
If a pregnant woman has syphilis, the fetus may be infected. The fetus may die in the womb (stillbirth), shortly after birth, or the baby may be born early, possibly with congenital abnormalities such as blindness, deafness or meningitis caused by the infection. Untreated babies may become developmentally delayed, have seizures, or die.
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The symptoms of syphilis depend on the stage of infection; primary, secondary, and late (tertiary).
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.
Untreated primary syphilis will progress to the next stage of disease. The secondary stage of infection with syphilis has different symptoms to the primary stage of infection. These symptoms 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
- 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 fetus. It is important to continue to test for syphilis if there is a risk of infection during pregnancy.
For more advice on safe sex, STI checks and where to get them, and answers to frequently asked questions, go to Just the Facts.