Syphilis is an infection caused by a bacterium called Trepomena pallidum. Syphilis used to be a very common STI, but it became increasingly rare during the 20th century. The infection has, however, increased in recent years among men who have sex with men. Syphilis is still widespread in other parts of the world.


Syphilis does not have any symptoms to begin with, so you could have the infection without realizing. Visible symptoms arise in the form of small painless sores on or near the genitals, anus or mouth and/or a rash, fever, nausea and tiredness. The sores heal in four to eight weeks. The sores could, however, be so small that they can’t be seen. When the sores heal, the bacteria remain in the body, which means there is a risk of passing the infection on to others. You may also experience a skin rash at a later stage.

Seven to 10 weeks after the first sores you may get new symptoms; fever and swollen lymphatic glands are common symptoms. However, there are not always symptoms, or they are so mild that they go unnoticed. These first two phases are called early-stage syphilis, and during this time there is a high risk of passing the infection on to others during sexual contact.

If syphilis goes untreated it gradually enters a phase called late-stage syphilis, and this is when the infection can cause damage to the heart and brain, for example. Treatment may prevent further damage, but any damage that’s already been done is permanent.


Syphilis is transmitted through skin contact and through anal, vaginal and oral sex. The infection can also be passed from mother to fetus during pregnancy. Syphilis can also be transmitted via blood. Since the infection is easily transmitted and it is hard to know if you have it, it’s important to get tested regularly and to protect yourself during sexual contact by using a condom. It can take anything from three weeks to three months before syphilis is detectable in a test. A syphilis test is a blood test and is always free of charge.

If you turn out to have syphilis, you will have to take part in an infection trace. In order to find others who may have syphilis, you’ll be asked who you’ve had sex with recently. It may feel a bit strange, but it’s a good way of showing consideration for the people you’ve had sex with. It gives them an opportunity to check that they’re healthy. This is what an infection trace is – sounds kinda weird, but it’s actually a great thing!


Syphilis can be cured with antibiotics as it’s caused by a bacterium. The infection heals if treatment is followed.

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