Syphilis

What is syphilis?

Syphilis is a bacterial sexually transmitted infection (STI) caused by the bacterium Treponema pallidum. It is most commonly transmitted through sexual contact—vaginal, anal, or oral sex—via direct contact with an infectious sore (chancre). Transmission is also possible from a pregnant person to the fetus during pregnancy or childbirth, leading to congenital syphilis. The infection can also be transmitted through blood contact, for example via blood transfusions or shared needles, although this is rare today.

Syphilis progresses through several stages—primary, secondary, latent, and tertiary. Each stage has characteristic symptoms, and without treatment the infection can move from one stage to another. In some cases, syphilis can remain hidden for a long time without visible symptoms, but the bacteria stay in the body and may cause serious complications years later.

In advanced stages, syphilis can damage the heart, blood vessels, brain, eyes, ears, liver, bones, and joints, potentially leading to permanent health damage or death. At any stage, syphilis can affect the nervous system (neurosyphilis) as well as vision and hearing.

Syphilis occurs in people of all ages but most commonly affects sexually active young adults. The risk of infection increases with unprotected sex or coexisting HIV infection.

There is currently no vaccine against syphilis. However, infection can be prevented through safer sexual practices, especially consistent use of condoms or dental dams, regular testing, and early treatment of infected individuals and their sexual partners.

Symptoms

It is very important to note that syphilis can occur without any visible symptoms, especially in the early stages. Symptoms may appear, disappear, and then return later, which often leads people to be unaware of the infection. When symptoms do occur, they vary depending on the stage of the disease.

Primary stage

The first symptoms usually appear 2 to 12 weeks after contact with an infected person. The typical sign is a sore (chancre) at the site where the bacteria entered the body, most often on the genitals, around the anus, or in the mouth.

The sore is usually:

• firm,
• painless,
• with a smooth base and clean edges.

Because it does not cause pain or burning, many people do not notice it. Nearby lymph nodes may become enlarged but are usually painless. The sore typically heals on its own within 3 to 6 weeks, even without treatment, but the infection remains in the body and continues to progress.

Secondary stage

If the infection is not recognized and treated, the bacteria spread through the bloodstream, causing a wide range of symptoms. This stage appears weeks to months after the primary sore has healed.

Common symptoms include:

• General flu-like symptoms: fever, fatigue, muscle and joint pain, sore throat, loss of appetite, and weight loss.
  
• Skin rash, often on the palms of the hands and soles of the feet, but it can spread to the trunk and other parts of the body. The rash usually does not itch and can appear as small pink spots or scaly patches.
  
• White patches or lesions on the mucous membranes of the mouth or genital area.
  
• Hair loss.
  
• Swollen lymph nodes throughout the body.
  

These symptoms may last several weeks and often resolve on their own. In some people, they recur intermittently over months or even years.

Latent stage

After secondary symptoms resolve, the infection may enter a latent (hidden) stage. There are no clinical symptoms, but the bacteria remain in the body. The infection may still be transmissible, especially during the early latent phase.

The latent stage can last for years. Some people remain asymptomatic for life, while in others the infection progresses to the late (tertiary) stage.

Tertiary stage

If syphilis remains untreated for years or decades, it may progress to the tertiary (late) stage, which is the most severe and potentially life-threatening. At this stage, the bacteria cause serious damage to internal organs, including the heart, blood vessels, brain, nervous system, eyes, liver, bones, and joints.

Typical complications include:

• Neurosyphilis: involvement of the nervous system causing memory problems, lack of coordination, personality changes, hallucinations, paralysis, or dementia.
  
• Ocular and otic syphilis: affecting vision or hearing, sometimes leading to significant impairment or loss.
  
• Cardiovascular syphilis: damage to the aorta and heart valves, potentially causing aneurysm or heart failure.
  
• Gummatous lesions (gummas): soft, destructive nodules or lesions in the skin, bones, or internal organs, which may leave scars and deformities.
  

Some damage in the tertiary stage may be irreversible, even after successful treatment. This is why early diagnosis and treatment are crucial.

Testing

Testing for syphilis is essential because many cases occur without symptoms. A person can be infectious while feeling completely healthy. Early testing protects both personal health and that of sexual partners.

Syphilis testing can be done using blood tests, samples from sores, and in many settings, rapid tests.

Blood tests

The most reliable and commonly used diagnostic method is a blood test that detects antibodies against Treponema pallidum. These antibodies develop after exposure and may persist for a long time, even after successful treatment.

Some clinics offer same-day rapid testing, while others send samples to a laboratory for detailed analysis. It is important to note that after infection, it can take several weeks (up to 12 weeks) for antibodies to become detectable. If a test is negative shortly after a risk exposure, repeat testing is recommended.

Laboratory testing usually follows a two-step approach: an initial screening test followed by a confirmatory test if the result is positive.

Swab from a sore (if present)

If a sore is present, a sample can be collected using a swab. This sample may be examined microscopically or using molecular methods (such as PCR) to directly detect the bacterium Treponema pallidum. This is especially useful in early infection before antibodies appear in the blood.

Rapid finger-prick tests

Rapid tests using a drop of blood are increasingly used. Results are available within minutes and indicate whether antibodies to Treponema pallidum are present.

These tests do not detect the bacterium itself, only the immune response. A reactive result must be confirmed with laboratory testing to determine whether the infection is current or past.

In Slovakia, rapid tests are also used in outreach and low-threshold services. OZ Odyseus provides free, anonymous, and confidential rapid testing for syphilis, HIV, and viral hepatitis B and C.

If you are interested in testing, you can contact us via our website, the chat on drogy.org, or the social media channels of OZ Odyseus. Our staff are available to provide support and answer questions.

Treatment

Syphilis is fully curable in most cases if detected early and treated correctly. Timely diagnosis and treatment are essential because some damage caused by advanced syphilis may be irreversible.

The standard treatment for all stages of syphilis is penicillin, administered by intramuscular injection. This is the most effective and recommended therapy to eliminate Treponema pallidum. For people allergic to penicillin, alternative antibiotics such as doxycycline, ceftriaxone, or azithromycin may be used, depending on medical guidance. The standard treatment for all stages of syphilis is penicillin, administered by intramuscular injection. This is the most effective and recommended therapy to eliminate Treponema pallidum. For people allergic to penicillin, alternative antibiotics such as doxycycline, ceftriaxone, or azithromycin may be used, depending on medical guidance.

Treatment duration depends on the stage of the disease. After treatment, follow-up blood tests are recommended to ensure antibody levels decrease and the infection has been successfully cleared. Tests are often repeated after 3, 6, and 12 months.

Some people experience short-term symptoms shortly after the first dose of penicillin, such as fever, chills, headache, muscle and joint pain. This is known as the Jarisch–Herxheimer reaction, caused by the rapid breakdown of bacteria. These symptoms usually resolve within 24 hours and are not a reason to stop treatment.

All sexual partners who may have been exposed must be tested and treated if necessary to prevent further transmission and reinfection.

Reinfection is possible even after successful treatment, so safer sex practices—especially condom or dental dam use—and regular testing remain important.

Healthcare providers often recommend temporary sexual abstinence (usually for 7 days after treatment or until sores have fully healed) and advise against resuming sexual activity until all tests confirm the infection has been cured.

Conclusion

Syphilis can be a serious disease, but when detected early and treated properly, it is completely curable. Knowing your body, noticing even small changes, and seeking testing or advice without fear are essential steps.

Healthcare services and community organizations like OZ Odyseus offer free, anonymous, and confidential testing. Non-judgmental care, accurate information, and professional support help ensure that sexual health can be addressed with dignity and respect.

If you have any doubts, questions, or interest in testing, reach out to trusted professionals or services. Health is something to care for—not something to be ashamed of.

Sources:

https://www.who.int/news-room/fact-sheets/detail/syphilis

https://www.nhs.uk/conditions/syphilis

https://www.ncbi.nlm.nih.gov/books/NBK534780

https://www.healthdirect.gov.au/syphilis

https://www.mayoclinic.org/diseases-conditions/syphilis/symptoms-causes/syc-20351756

https://www.chelwest.nhs.uk/services/hiv-sexual-health/syphilis-test