Everything you need to know about syphilis

Karolina Baker, Alphabiolabs

By Karolina Baker, Health Testing Specialist at AlphaBiolabs
Last reviewed: 24/01/2023

This guide contains everything you need to know about syphilis including what it is, signs and symptoms of the infection, how it’s treated, and how often you should get an STI/STD test for syphilis.

Table of contents
  • What is syphilis?
  • How common is syphilis?
  • What does syphilis look like?
  • Is syphilis contagious?
  • How do you get syphilis? How is syphilis spread?
  • Can you get syphilis from kissing?
  • Can you get syphilis without having sex?
  • What are the signs of syphilis?
  • What are the stages of syphilis?
  • How long does syphilis take to show up?
  • How long does syphilis last?
  • What is the treatment for syphilis?
  • How long is syphilis contagious after treatment?
  • Does syphilis affect fertility?
  • How can I test for syphilis?

What is syphilis?

Syphilis is a sexually transmitted infection (STI), that can cause serious and potentially life-threatening problems if left undiagnosed/untreated.

The infection is caused by Treponema pallidum (T. pallidum) bacteria, and develops in four stages: primary syphilis, secondary syphilis, latent syphilis and tertiary or late syphilis.

Symptoms of syphilis infection can include small sores, ulcers and/or wart-like growths (on your genitals and/or other parts of your body), a rash on the palms of the hands/soles of the feet, swollen glands, patchy hair loss and flu-like symptoms including high temperature, headaches, and tiredness.

When the infection is detected/diagnosed early, it can be treated with antibiotics. If the infection develops to a later stage, it can still be treated with antibiotics, but treatment can take much longer.

If you think you may have a syphilis infection, are experiencing symptoms that are causing you severe pain and discomfort, or require a face-to-face examination, we advise you to contact your GP or local sexual health clinic as soon as possible.

How common is syphilis?

Syphilis is among the most common STIs/STDs in the UK.

According to figures released by the UK Health Security Agency, there were 7,506 diagnoses of infectious syphilis (primary, secondary, early latent) reported in 2021. This represented an 8.4% increase on the number of diagnoses registered in 2020.

Between 2020 and 2021, there was also a 6.1% increase in diagnoses of infectious syphilis among young people aged 15-24.

What does syphilis look like?

Not everyone who has syphilis will experience symptoms. However, for those who do experience symptoms, some visible signs of a syphilis infection can include:

  • Small sores, ulcers and/or wart-like growths on the genitals and/or other parts of the body. These are also known as syphilitic sores or chancres
  • A rash on the palms of the hands/soles of the feet
  • Patchy hair loss

For more information on syphilis signs and symptoms, visit www.sexwise.org.uk.

Is syphilis contagious?

Syphilis is caused by a bacteria called Treponema pallidum (T. pallidum), which is highly contagious.

It is commonly passed on to other people through sexual activity including vaginal, anal, and oral sex.

It can also be passed on through skin-to-skin contact with an infected person who has an active syphilitic sore (chancre).

These chancres can occur on the genitals, anus, lips, and mouth. However, even without these chancres, the syphilis infection is still contagious and can be passed on to others via infected bodily fluids (semen, vaginal fluids, anal fluids, and blood).

How do you get syphilis? How is syphilis spread?

Syphilis is passed on to others via sexual contact such as unprotected vaginal, anal, and oral sex, if bodily fluids such as semen and vaginal fluids are transferred between partners.

It can also be spread during skin-to-skin contact with an infected person, who has an active syphilitic sore (chancre), and pregnant women can pass syphilis on to their unborn babies.

You cannot catch syphilis from swimming pools, hot tubs, or bathtubs, by sharing clothing or eating utensils, or from toilet seats.

You can learn more about syphilis and how it is spread by visiting www.sexwise.org.uk.

Can you get syphilis from kissing?

Although extremely rare, it is possible to catch syphilis from kissing.

This is because it is easy to catch syphilis during skin-to-skin contact with an infected person who is experiencing an outbreak of syphilitic sores (chancres).

However, the syphilis infection is not typically spread via kissing, and is most often transmitted from person-to-person through infected bodily fluids (semen, vaginal fluids, blood).

Can you get syphilis without having sex?

Because syphilis can be spread via skin-to-skin contact with an infected person, it is possible to catch syphilis without having penetrative (vaginal or anal) sex.

Ways you can catch syphilis without having sex include:

  • During oral sex with an infected person
  • By kissing, particularly if the person has developed syphilitic sores around or inside the mouth
  • During skin-to-skin contact including genital touching or manual stimulation of the genitals with hands
  • By sharing sex toys that have come into contact with an infected person
  • By sharing needles, razors, or other items that can cause nicks or cuts to the skin. This is because syphilis can also be spread in the blood

You cannot catch syphilis by sharing towels or clothing, from toilet seats or by sharing food, drinks or cutlery.

What are the signs of syphilis?

The signs and symptoms of syphilis vary, depending on the person and to what stage the infection has developed.

Signs of syphilis can include:

  • One or more painless, firm, round sores on the genitals and/or other parts of the body
  • A red or red-brown rash
  • Fever
  • Muscle aches
  • Swollen lymph nodes
  • A sore throat
  • Headaches
  • Fatigue

More advanced syphilis, also known as tertiary or late syphilis, can occur many years after the initial infection and lead to much more severe and even life-threatening complications.

If you think you may have been exposed to a syphilis infection or are experiencing symptoms that are causing you pain and discomfort, speak to your GP or local sexual health clinic as soon as possible.

What are the stages of syphilis?

The four stages of syphilis infection, which is caused by Treponema pallidum (T. pallidum) bacteria, are:

Stage 1: Primary syphilis

The infection is contagious at this stage and symptoms include one or more painless, firm, round sores on the genitals and/or other parts of the body. These can occur anywhere from 10 days to three months after the bacteria has entered the body.

Stage 2: Secondary syphilis

The infection remains contagious at this stage and symptoms include genital, anal, or oral (mouth) sores resembling warts, a red or red-brown rash, fever, muscle aches, swollen lymph nodes, a sore throat, headaches, and fatigue.

Stage 3: Latent syphilis

Latent syphilis can last for several years, during which the infection remains in the body, but the infected person does not display any symptoms. However, there is a risk of symptoms reoccurring, and treatment is still recommended to reduce this risk and the chances of passing the infection to other people.

Stage 4: Tertiary or late syphilis

This stage of the infection can occur many years after the initial infection. Some people have been known to develop tertiary syphilis as many as 10-30 years after first exposure and, although not contagious at this stage, symptoms can be much more severe and even life-threatening, causing damage to vital organs and systems including the heart and liver, as well as bones, blood vessels and joints.

If you are sexually active, regular syphilis testing can help give you peace of mind, or ensure the infection is detected early, so that you can seek the appropriate treatment.

When caught early, syphilis can be easily treated with antibiotics. If the infection develops to a later stage, it can still be treated with antibiotics, but treatment can take much longer.

Speak to your GP or local sexual health clinic as soon as possible if you believe you are experiencing symptoms of syphilis.

How long does syphilis take to show up?

The time it takes from when a person is first infected to when they might start to experience symptoms is called the ‘incubation period’.

The average incubation period for syphilis is 21 days (3 weeks), but this can vary from as few as 10 days, to as many as 90 days.

Symptoms of syphilis can often be mild, or extremely difficult to notice, making regular sexual health checks important. If left untreated, syphilis can cause severe and potentially life-threatening complications including heart, brain, nerve, and skin problems, and even organ damage.

If you are experiencing symptoms, speak to your GP or local sexual health clinic as they will be able to advise on next steps for diagnosis and treatment.

How long does syphilis last?

A syphilis infection will remain in a person’s body until it is treated, regardless of whether the person is currently experiencing symptoms.

How long symptoms of syphilis last depends on the stage to which the infection has developed.

  • An outbreak of syphilitic sores (chancres) during the primary stage can last from 3-6 weeks
  • Secondary stage symptoms including a red or red-brown rash can last 2-6 weeks, and can come and go for up to 2 years

Latent syphilis can last for several years, during which time the infection remains in the body, but the infected person does not experience any symptoms.

If left untreated, latent syphilis can develop into tertiary syphilis, which is very serious. During this stage symptoms can be much more severe and even life-threatening, causing damage to vital organs and systems including the heart and liver, as well as bones, blood vessels and joints.

What is the treatment for syphilis?

The treatment for syphilis can vary depending on the type of infection the person has, and the stage to which it has developed.

If you have been diagnosed with a syphilis infection, your GP or local sexual health clinic will be able to advise on next steps for treatment, depending on your personal circumstances. 

How long is syphilis contagious after treatment?

It is usually recommended that you abstain from sexual contact until after you have completed your treatment.

Your GP or local sexual health clinic will be able to provide guidance on when the infection is no longer contagious, depending on your treatment plan.

Does syphilis affect fertility?

Although syphilis itself does not cause infertility, complications from undiagnosed/untreated syphilis can lead to health problems that contribute to infertility.

If the infection develops to the later stage (tertiary syphilis), this can lead to organ and nerve damage, which can affect every system in the body including the reproductive system.

Syphilis can also be passed on from mother to baby during pregnancy and can lead to miscarriages, still births and birth defects.

How can I test for syphilis?

If you are experiencing symptoms that could indicate a syphilis infection, or you do not have symptoms and believe you have been exposed to an infection, it is important to speak to your GP or local sexual health service, as they will be able to provide guidance on testing and diagnosis.

You can also order an at-home syphilis test online, allowing you to collect your own sample at home to be tested in a laboratory.

Available for £65.00, with results in just two working days, this test can be used to detect syphilis and the herpes simplex virus (Type-1 and Type-2) if you are experiencing symptoms. The test requires a lesion swab sample to be collected from a visible lesion, sore or ulcer.

Your test kit will contain everything you need to collect your samples and return them to our UKAS-accredited laboratory.

IMPORTANT: If your test results show that a pathogen has been detected in your sample, you MUST contact your GP or local sexual health clinic for confirmatory testing, guidance, and treatment options as soon as possible.

You should also abstain from sexual contact to avoid passing the infection on to other people, and contact any sexual partners as soon as possible to inform them of the result.

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Karolina Baker

Karolina Baker

Health Testing Specialist at AlphaBiolabs

Karolina joined AlphaBiolabs in 2021, and holds the role of Health Testing Specialist.

As well as overseeing a range of health tests, Karolina plays an active role in the research and development of the company’s latest health test offerings.

Before joining AlphaBiolabs, Karolina worked as an Associate Practitioner at Mid-Cheshire Hospitals NHS Foundation Trust, and as a research assistant at the Turner Laboratory, within the Faculty of Biology, Medicine and Health at The University of Manchester.

Karolina’s main scientific interests include clinical genomics and genetic diagnostics. Her qualifications include a BSc in Molecular Biology and an MSc in Genomic Medicine.