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Syphilis Symptoms & Causes

Syphilis is the first disease to have been identified as a sexually transmitted infection in 1494. Caused by the bacterium Treponema pallidum, Syphilis behaves differently from other STIs and is often seen to affect parts of the body other than the male/female genitalia.

The first effective treatment for Syphilis became available after the discovery of Penicillin in 1943. In the last few years, Syphilis has started to make a resurgence in the UK and other countries.

Syphilis testing

This is the routine test for syphilis looking for presence of antibodies – results in 20 minutes.

Syphilis swab test

Those experiencing ‘chancres’ which are suspected to be Syphilis may require a DNA PCR test from the lesion.

Syphilis treatment

For those who have tested positive for Syphilis, we can offer safe and effective treatment.

Key features of the infection


Syphilis is contagious to others, without treatment, in the first 2 years after getting the infection. This period of infectiousness can last upto 4 years in those with HIV infection. Receiving early treatment reduces this period of infectivity, apart from preventing progression to next stage and the complications.

Syphilis becomes non-contagious 2 years after getting the infection, even without adequate treatment. The progression to next stages of Syphilis however does go on in the absence of adequate treatment.

Clinical symptoms and staging of Syphilis

Most patients with Syphilis will have no symptoms and are diagnosed on a routine blood test as part of a sexual health check-up. There are some patients who present with a genital ulcer or a skin rash to a sexual health clinic which prompts a suspicion of Syphilis and the test is undertaken.

However, common symptoms produced by early Syphilis like fever, sore throat, lymph nodes, mouth ulcers and skin rash, being away from genitalia, do not raise the suspicion of a sexually transmitted infection. The patients do not seek advice or attend a non-specialist clinic where Syphilis is not considered.  Most of these symptoms disappear in a few weeks and the patient thinks that their problem is gone. The reality is that Syphilis in such patients is progressing to the next stage with greater risk of complication and greater risk to your health. That is why a delay in the diagnosis and treatment of Syphilis is common.

The clinical staging of Syphilis refers to how advanced the effect of Syphilis has been in a given patient, and takes into account the following:

  1. How long you have the Syphilis for
  2. Nature of symptoms
  3. Presence of signs in different body systems
  4. Details of latest Syphilis blood test
  5. Details of previous Syphilis blood tests where available.

The stages of Syphilis are described as

  1. Incubating Syphilis
  2. Primary Syphilis
  3. Early latent Syphilis
  4. Secondary Syphilis
  5. Late latent Syphilis
  6. Tertiary Syphilis
  7. Congenital Syphilis (refers to infection acquired at the time of birth)

Local to a mutli-system disease

When someone gets the Syphilis infection, it is a local infection, producing symptoms in the part of the body where the initial exposure to the infection had occurred.

As it progresses through different stages with the passage of time over months and years, it begins to affect more than one system in the body. Thus Syphilis, soon after its first stage called primary Syphilis, can affect virtually any system in the body including skin, eyes, liver, brain, nerves and heart. In later stages, the effect produced by Syphilis becomes irreversible despite treatment.


Syphilis was a common STI in Europe for almost 500 years until the end of the second world war. There was a massive spike of Syphilis cases between 1943-1950 in the UK, but thanks to the discovery of penicillin and venereal disease clinics, the cases of infectious syphilis virtually disappeared by 1950 and remained so until 2000. The cases began to reappear again from around 2000 and have kept increasing since then.

Between 2010 and 2020, there has been a massive increase, more than 300% increase, in cases of syphilis in the UK. There were about 8000 cases of syphilis diagnosed in the UK in 2018, most of them being in gay men. However, there has been alarming rise of these cases in the heterosexual population as well.

Syphilis, after HIV, is the second most serious sexually transmitted infection.

New worldwide cases
In 2012, according to WHO there were
approx. 5.6 million new cases of Syphilis.

Total worldwide cases
In 2012, according to WHO there was an estimated 18 million total cases of Syphilis.

Total worldwide Syphilis in pregnancy related problems
In 2012, according to WHO there was an estimated 930,000 maternal Syphilis infections resulting in 350 000 adverse pregnancy outcomes, including stillbirths, neonatal deaths, preterm births and infected infants.

Key demographics affected
Approximately 75% of all Syphilis diagnoses in 2018 were made in MSM (Men who have Sex with Men).

In 2017, the median age of MSM (Men who have Sex with Men) diagnosed with Syphilis was 37 years old and the majority were white (74%) and 45% were born in the UK.

49% of cases of Syphilis in England were seen in those who live in London.


Incubating Syphilis

From the day of exposure to Syphilis, it usually takes about 3 weeks for the signs and symptoms of Syphilis to appear. But the symptoms could present as soon as 9 days or 90 days after exposure. This time interval is called the incubation period and the Syphilis blood tests may be negative in this time period.

If an infected patient is testing within this incubation period and their Syphilis blood test is negative, they may develop signs and symptoms of Syphilis days or weeks later.

If the infection is left untreated, many such patients will have positive Syphilis blood tests when repeated days or weeks later and subsequently develop symptoms and signs of Syphilis.

One option of managing such situations is to offer treatment based on the history of exposure even though their Syphilis test may be negative. This successfully aborts any Syphilis infection developing in the first place. Such an approach for managing exposure to a confirmed case of syphilis is also described as epidemiological treatment.

Primary syphilis

Symptoms of Syphilis can start as painless cuts, grazes, skin changes or ulcers at the area where the infection entered the body. This can last 4-6 weeks.

These symptoms are often associated with the enlargement of local lymph nodes – lymph nodes help your body to fight off infections. Enlargement of these lymph nodes is very important as they keep the infection localised in the area, and prevent its spread through the bloodstream into the rest of the body.

The lesion at the point where the infection entered the body is called a ‘chancre’ and together with local enlarged lymph nodes, this stage of Syphilis is described as ‘Primary Syphilis’.

These lesions and enlarged lymph nodes, in most patients, are without much pain or tenderness. As a result of this, the symptoms are not noticed by patients and they do not seek professional advice. If there is any pain or tenderness, then this may indicate the presence of a secondary infection (e.g. Herpes).

Examples of Primary Syphilis:

(a) Male genitalia

The classical picture of Syphilis is a single painless ulcer on the penis with enlargement of lymph nodes in the groin area, on one side or the both.

However, in reality, practice does not follow theory and it is common to see many lesions over the genitals indicating the infection has entered the body from multiple points. Sometimes the lesions are present on the genitalia but without any swelling over the groin area.

(b) Female genitalia

Erosions or ulcers or patches can occur over the vulva, vaginal wall and cervix. However they often go unnoticed due to the following reasons:

  • There is minimal, if any, pain and thus patients do not notice.
  • They are located internally (vaginal wall and cervix) making it difficult for patients to see.
  • The lymph nodes in the groin do not swell up when there are ulcers on the vaginal wall and cervix – these areas get drained to lymph nodes inside the pelvis which is even harder to detect.

(c) Mouth

When the infection enters through the mouth or tongue, the lesion (erosion, ulcer or patch) develops on the lining of the mouth or tongue. This leads to swelling of lymph nodes in the neck. This is often seen in MSM (Men who have Sex with Men) and can easily occur in heterosexual women giving unprotected oral sex.

Sometimes lesions due to primary Syphilis in the mouth tend to be sore due to infection from the other bacteria normally present in the mouth.

(d) Anus

When the infection enters through the back passage or surrounding skin, the lesion (erosion, ulcer or patch) develops on the lining of the back passage, sometimes a bit higher up that they cannot be seen from outside. Lymph node swelling is not noticed as well, as the enlarged lymph nodes are deep inside the pelvis.

This is often seen in gay men and can easily occur in the heterosexual women during anal sex without a condom.

Latent Syphilis

The lesions in primary Syphilis do not produce headache or fever, and tend to disappear in 4-6 weeks even without any antibiotic treatment. Patients go through a period when they have no symptoms and signs called Latent Syphilis.

Early Latent Syphilis

When the patient’s test for Syphilis is positive, and they have no symptoms or signs, they are in the stage of Early Latent Syphilis if it is within 2 years of acquiring the infection.

Late Latent Syphilis

When the patient’s test for Syphilis is positive, and they have no symptoms or signs, they are in the stage of Late Latent Syphilis if it is after 2 years of first acquiring the infection.

Latent Syphilis of uncertain duration

When the patient’s test for Syphilis is positive, and they have no symptoms or signs, they are in the stage of Latent Syphilis of uncertain duration if it is difficult or even impossible to work out when the patient may have  acquired the infection.

Why is it important to distinguish between ‘Early’ and ‘Late’ Latent Syphilis?

  • Syphilis onto someone else only in first 2 years of getting the infection (early latent infection).
  • One can only get secondary Syphilis in the first 2 years after getting the infection.
  • Damage to various internal parts of the body in the first 2 years of getting Syphilis can be reversed with adequate antibiotic treatment.
  • Damage to various internal organs in Syphilis after 2 years of getting the infection is not likely to be reversible. Treatment, however, will prevent further progression to the damage.

Secondary Syphilis

Symptoms and signs of Secondary Syphilis usually appear within 3-6 months but can occur anytime within the first 2 years after getting Syphilis. Patients, once diagnosed, respond very well to the treatment. In some patients, waves of secondary Syphilis can occur more than once.

Whilst Primary Syphilis is due to the presence of bacteria only in a local area where it entered the body, in Secondary Syphilis the bacteria causing Syphilis (spirochaetes) spills into the blood circulation and has spread widely in the body through the bloodstream.

This is the most infectious stage of Syphilis as there are huge amounts of bacteria in the blood, body fluids, mucous membranes and lesions on skin.

The presence of spirochaetes in the bloodstream produces an immune response from the body, producing a picture of ‘prolonged flu like illness with a skin rash’ in the forms of:

  • Fever
  • Sore-throat
  • Headache
  • Night sweats
  • Poor appetite
  • Weight loss

As the infection spreads throughout the body, symptoms specific to various organ systems develop. Some patients will develop symptoms more specific to certain organ systems whilst others may develop symptoms across multiple organ systems. These may include:

  • Skin rash, ulcers in the mouth
  • Loss of hair (scalp, eye brows, eye lashes etc)
  • Redness of eyes
  • Floaters and reduction in vision (ocular Syphilis)
  • Impairment of hearing
  • Abnormal liver function
  • Heart and Brain affected (rarely in secondary Syphilis)

Furthermore, Secondary Syphilis is very dangerous to pregnant mothers and infects the foetus in almost 100% of cases. This can lead to catastrophic consequences like miscarriage, stillbirth, premature birth, death of the newborn and congenital Syphilis. This is the reason that Syphilis testing has been an integral part of antenatal care across the world for more than 50 years.

Tertiary Syphilis

When the Syphilis infection has been present in the body for more than 2 years, the spirochaetes become fewer in number. These bacteria lodge themselves in various important parts of the body including the brain, spine, nerves, heart, large arteries, liver and bones where they produce chronic inflammation around them.

This process can go on for years without producing any symptoms. By the time symptoms are produced, significant damage has already been done. Diagnosis of tertiary Syphilis is made typically 10-40 years after getting the infection. The emphasis on early diagnosis and treatment of Syphilis is to prevent development of tertiary Syphilis.

Congenital Syphilis

This is the most serious form of Syphilis, affecting the foetus or newborn baby. Women who have Syphilis during pregnancy are at great risk of miscarriage, stillbirth or passing Syphilis onto their child. Syphilis is easily detectable with a blood test and effective treatment available to prevent the baby from getting infected.

Can I have Syphilis without any symptoms?

Yes. Most people diagnosed with Syphilis will have no symptoms at the time of taking the test. Some will be able to recollect having had symptoms in the past which may be consistent with a diagnosis of Syphilis.

Often people come forward for a Syphilis test because someone they have sexual contact with has been diagnosed with Syphilis (contact tracing).

Other circumstances through which many people come to know of their Syphilis diagnosis are the antenatal blood tests, at the time of blood donation and routine sexual health check-ups.


Complications of Syphilis usually arise when a Syphilis infection has gone undetected or untreated for years or decades. This is known as Tertiary Syphilis. It can spread to other areas of the body and may cause:

  • Meningitis
  • Strokes
  • Dementia symptoms
  • Loss of coordination
  • Numbness
  • Vision problems or blindness
  • Heart problems

If you are experiencing symptoms of, or have been exposed to, Syphilis, we would recommend getting tested for syphilis and begin syphilis treatment without delay.

Images of Syphilis

Here are images of some severe cases of Syphilis (before receiving treatment from us).

Please be advised that the images are highly graphic in nature.


How do I get Syphilis?

  • Unprotected vaginal, anal or oral sex
  • Contact with infected skin lesions
  • During childbirth from infected mother (via the placenta)
  • Transfusion of infected blood (very rare in the UK)

There is no evidence that Syphilis can be spread from:

  • Close contact (e.g. kissing and/or hugging)
  • Sharing showers, towels, swimming pools
  • Toilet seats
  • Cutlery

What increases my chances of getting Syphilis?

  • If you are a man and have sex with other man
  • Being on PrEP
  • Sexual contact with partners from abroad
  • Sexual contact with an Escort or a commercial sex worker

How can I prevent getting Syphilis?

  • Have protected vaginal, oral and anal sex
  • Use a condom, femidom and/or dental dam with a new partner
  • You and your new partner get tested before having sex
  • Recommend your partner to get tested if they’ve had another partner recently
  • Take antibiotics if you recently had sex with someone with Syphilis

Next Steps 

Telephone / Video Consultation

Same Day Appointments Available

In Person Consultation + Testing/Treatment

Same Day Testing & Treatment Available

Page reviewed by Dr. Manoj Malu (Clinical Director)

Last reviewed date: 8 July 2020
Next review due: 8 July 2023

Whilst this content is written and reviewed by sexual health specialists, it is for general guidance only. It is not intended to replace the advice of your clinician.

References & Further Reading