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Syphilis is a sexually transmitted infection caused by a bacteria (bug) called treponema pallidum. The bacteria enter the body through tiny breaks in the skin, mainly in the anal area, genital area, or the mouth.

If untreated, syphilis can stay in your body causing serious problems.

Syphilis is very infectious, and you can catch it by having sexual contact with an infected person. This may include vaginal, anal, or oral sex, or just close skin-to-skin contact.

Syphilis can also be spread from mother to baby during pregnancy, if the mother is infected.

Symptoms of syphilis

When you first get syphilis, it may cause painless ulcers (sores) on your genital area or other places of sexual contact, such as your mouth or anus (bottom). This is known as primary syphilis.

If syphilis isn't treated, it can stay in your body and progress to secondary syphilis, which may cause a rash and other symptoms including new sores.

Some infected people will get tertiary syphilis which can appear years later. This can cause a wide range of symptoms.

Diagnosing syphilis

You'll need a blood test to check for syphilis.

If you're sexually active, it's a good idea to get tested. You can get tested by your GP, Sexual Health Centre, Family Planning Clinic or school clinic. Even if you feel embarrassed, it's better to get checked than to have untreated syphilis.

Treating syphilis

Syphilis is treated with antibiotics. The length of treatment varies depending on the type of infection and the antibiotic used. In most cases, penicillin injections are used.

After treatment with penicillin injections, some people (particularly in early syphilis) have a flu-like illness for 24 hours. This includes fevers, aches and pains, and generally feeling sick. These symptoms go away and don't require any treatment except rest.

After treatment, follow-up blood tests are essential for at least one year to make sure you're healed.

Your sexual partners will also need to be tested and treated.

Using a condom every time you have sex is the best way to protect yourself from getting or passing on syphilis.

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Written by HealthInfo clinical advisers. Last reviewed February 2019.

See also:

Telling your sexual partner (partner notification)

Page reference: 53679

Review key: HISYP-53679