Silent infection: the importance of Syphilis testing

Because its symptoms are often mild and hard to notice. The first sign is usually a small sore that’s painless and can easily go unnoticed, especially if it’s somewhere you can’t see, such as inside your mouth or around your bottom. Symptoms can also improve or go away completely, but if you haven’t been treated, the infection is still in your body.

That means you can have Syphilis without realising and pass it on. It spreads easily: UK guidelines say about a third of the sexual partners of someone with infectious Syphilis catch it.

Syphilis diagnoses rose sharply over the past decade. In 2024, more than 13,000 cases were diagnosed in England, the highest number since the 1940s.

• In 2025, there were 8,262 diagnoses of infectious Syphilis in England, down 13.5% from 9,553 in 2024.
• Most were in gay, bisexual and other men who have sex with men, but diagnoses in women who have sex with men rose by 4.8%.
• Between 2015 and 2024, diagnoses of infectious Syphilis more than doubled in heterosexual men and tripled in women who have sex with men.

Read more in “The strange rise of Syphilis cases in heterosexual men in the UK”

Syphilis is most often passed on through vaginal, anal or oral sex without a condom, when you come into contact with a sore on someone’s penis, vagina, bottom or inside their mouth. It can also be passed on:

• to a baby during pregnancy
• by injecting drugs with a needle that’s been used by someone with Syphilis
• rarely, through a blood or organ transplant, although all donations in the UK are checked for Syphilis

Sharing sex toys can pass it on too, so wash them and cover them with a new condom before anyone else uses them. Read more in “Can you pass on Syphilis without a sore?”

It can take 3 weeks or more for the first symptoms to appear, and later symptoms may come up to 3 months later.

Early symptoms

• small sores (ulcers) on your penis, vagina or around your bottom, which are usually painless
• sores in other places, such as your mouth or lips

Later symptoms

• a rash on the palms of your hands and soles of your feet, which can spread all over your body and isn’t usually itchy
• white or grey warty growths, usually on your penis, vagina or around your anus
• white patches in your mouth
• flu-like symptoms, such as a high temperature, headaches and tiredness
• swollen glands
• patchy hair loss on your head, beard and eyebrows

Read more in “What does Syphilis look like?”

After the early stages, Syphilis can go into a latent stage, when there are no symptoms. Without treatment, it can cause serious problems years later, including:

• heart problems, such as an aortic aneurysm or heart failure
• brain problems, such as fits, memory problems and dementia
• nerve problems, such as shooting pains and gradual damage to the joints
• sight and hearing problems

Syphilis can also pass to a baby during pregnancy, and it increases the risk of miscarriage, premature birth and stillbirth. That’s why a Syphilis test is offered in every pregnancy in England.

Because Syphilis is so easy to miss, testing is the only way to know for sure. It’s worth getting tested if:

• you’ve had sex without a condom with a new or casual partner
• a partner tells you they have Syphilis
• you notice a sore, rash or growth you’re not sure about

UK guidelines suggest testing for STIs at least once a year if you’re sexually active, and every 3 months if you’re at higher risk, for example if you’ve had more than 10 partners in the past year or you take PrEP. Finding Syphilis early means it can be treated before it causes serious problems. Read more in “Can you have Syphilis and not know it?”

Syphilis is treated with antibiotics. Early Syphilis is usually treated with a single injection of penicillin, and there are tablets if you’re allergic to penicillin. Syphilis that has been there longer may need an injection once a week for 3 weeks.

Don’t have sex until 2 weeks after you and your partner have finished treatment. You’ll have follow-up blood tests over the next year to check the treatment has worked. Having Syphilis once doesn’t protect you, so you can catch it again. Read more in “Can Syphilis be fully cured?”

Better2Know offers:

• Syphilis: a blood test for Syphilis antibodies from 9 days after sex, with results in 1 day. You can book it at one of our clinics or order a home test kit.
• Peace of Mind: tests for Chlamydia, Gonorrhoea and Syphilis from 14 days after sex, with results in 2 days.
• Platinum Screen: tests for 12 infections, including Syphilis, HIV and Hepatitis C, from 28 days after sex, with results in 3 days.
• Blemish Screen: if you have a sore or growth, it tests a swab for Syphilis, Herpes 1, Herpes 2 and HPV, with results in 5 days.

If you test before 45 days, a negative HIV result needs a repeat test. A Syphilis test in the first 3 months after sex can miss the infection, so you may need a repeat test. Not sure which test you need? Our Patient Care Team is available 24/7 on 020 7099 0955.

Can Syphilis go away on its own?

The symptoms can improve or go away completely, but without treatment the infection stays in your body and can cause serious problems later.

Can you get Syphilis more than once?

Yes. Having had Syphilis before doesn’t protect you, so you can catch it again.

Is Syphilis only a risk for gay and bisexual men?

No. Most diagnoses in England are in gay, bisexual and other men who have sex with men, but diagnoses in heterosexual men and women have risen sharply over the past decade.

Syphilis is easy to miss, but it’s simple to test for and treat. If you’ve had sex without a condom with a new partner, or you’ve noticed a sore or rash you’re not sure about, getting tested is the only way to know.

Book a Syphilis test at a clinic near you or order a home test kit. Our Patient Care Team is available 24/7 on 020 7099 0955.

Not in the UK? Choose your country from the selector at the top of the page for local tests and prices.

This article originally appeared on 27 April 2018 and was last updated on 1 October 2026.

This article is general information and not a substitute for personal medical advice.

Sources

1. NHS, Syphilis, reviewed 17 March 2026. https://www.nhs.uk/conditions/syphilis/
2. British Association for Sexual Health and HIV, UK guidelines for the management of syphilis, 2024. https://www.bashh.org/_userfiles/pages/files/syphilis_2024.pdf
3. UK Health Security Agency, Sexually transmitted infections and screening for chlamydia in England: 2025 report, 2 June 2026. https://www.gov.uk/government/statistics/sexually-transmitted-infections-stis-annual-data-tables/sexually-transmitted-infections-and-screening-for-chlamydia-in-england-2025-report
4. UK Health Security Agency, UKHSA Syphilis Response Plan, 23 March 2026. https://www.gov.uk/government/publications/syphilis-public-health-england-action-plan/ukhsa-syphilis-response-plan
5. NHS, Screening for hepatitis B, HIV and syphilis, reviewed 23 January 2024. https://www.nhs.uk/pregnancy/your-pregnancy-care/screening-for-hepatitis-b-hiv-and-syphilis/
6. British Association for Sexual Health and HIV, Summary guidance on testing for sexually transmitted infections, 2023. https://www.bashh.org/_userfiles/pages/files/resources/bashh_summary_guidance_on_stis_testing_2023.pdf
7. British HIV Association, British Association for Sexual Health and HIV and British Infection Association, Adult HIV testing guidelines, 2020. https://bhiva.org/wp-content/uploads/2024/10/HIV-testing-guidelines-2020.pdf