What is syphilis?

Syphilis is a sexually transmitted infection (STI) that when left untreated can lead to serious long-term health complications.

Syphilis doesn’t always cause obvious symptoms. Because it can cause lasting damage when left untreated, it’s important to get tested if you think you might have been exposed, even if you feel healthy.

How do you get syphilis?

Syphilis causes one or more small painless sores to develop on the skin, usually around the genitals. Coming into contact with one of these sores puts you at risk of infection. Syphilis can be spread during vaginal, anal or oral sex. You can also catch it by sharing sex toys.

Using male and female condoms and dental dams can help lower the risk of transmission. However, because syphilis is spread by skin-to-skin contact, condoms and dental dams will only offer protection if they cover the area affected by sores.


The symptoms of syphilis are not always easy to recognise, which means it’s possible to pass on the infection without knowing it.

There are two early symptoms that can develop within a few weeks of infection:

  • One or more small painless sores, usually found around the genitals or anus but also on the mouth, fingers or buttocks
  • Swollen glands in the neck, armpits or groin

If these early symptoms pass and you remain untreated you might experience secondary symptoms:

  • Blotchy red rash (often found on the palms or the soles of the feet)
  • Skin growths around the vulva or anus
  • White patches in the mouth
  • Headaches, joint pain, tiredness and fever (similar to the flu)

These symptoms can pass after a few weeks or come and go for several months. After these disappear you remain infected with “latent syphilis”, which can go on to cause serious problems such as meningitis, dementia and stroke.


To get a free test for syphilis you should visit a GUM or sexual health clinic. The test usually involves a physical examination, blood test and swab of any sores. You might also receive a test for other STIs at the same time.


Once you’ve been diagnosed with syphilis you can receive treatment with antibiotics. Usually you’ll receive one to three injections of penicillin, or alternatively a course of antibiotic tablets lasting 10-28 days.

Content reviewed by Jemma Shafier, a Doctor Care Anywhere GP