Online Dermatologist > Syphilis

Medically reviewed by The Dermatologists and written by Dr. Alexander Börve

Syphilis is a sexually transmitted infection caused by bacteria, and the number of infected individuals has increased in recent years. The most common way to get infected is by having vaginal or anal sex without a condom or through oral sex. Syphilis can also be transmitted through blood transfusions and through unclean syringes with needles.

The disease is divided into three stages and can last for many years with more or less complications throughout this time. At worst, syphilis may cause serious damage to the heart and brain. You are most contagious the first ten weeks, but the disease is contagious up to two years after infection if not treated.

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Symptoms

You can be infected with syphilis without developing any symptoms. Approximately three to four weeks after infection, there is usually first an ulcer (usually on the genitals) and swelling (usually in the groin). The ulcer may be so small that it is not noticeable and it heals on its own after four to eight weeks. However, the disease can then spread to your blood and cause various skin rashes.

Stages of Syphilis

Primary Stage of Syphilis

After exposure to the Treponema pallidum bacteria, the first sign of syphilis is typically a chancre. This is a painless, firm, round sore that appears at the point of infection, usually on or around the genitals, but it can occur in other areas as well.

• Appearance
  • The chancre starts as a small bump and develops into an ulcer with a raised border.
  • It’s usually solitary, meaning there’s just one sore.
  • Because it’s painless, you might not even notice it.
• Timeline
  • Chancres typically appear between 10 and 90 days after exposure, with the average being 21 to 25 days.
  • Even without treatment, the chancre will heal on its own within 3 to 6 weeks.

Even though the sore disappears, the infection is still present and spreading throughout your body.Mild to moderate swelling of lymph nodes in the area of the chancre is common.

It’s important to remember that even if the chancre is not painful or goes away on its own, syphilis requires treatment to prevent serious health problems. If you notice any unusual sores or ulcers, especially on your genitals, it’s essential to seek medical advice promptly.

A small, round sore (chancre) in the groin area, indicating primary syphilis. Early symptoms like this can heal on their own but require medical attention to prevent the disease from spreading.

Syphilis, primary stage, genital ulcer, ICD-10 A51.0: This image shows a small, round ulcer on the penis, indicative of primary syphilis. The ulcer is pink, slightly raised, and has a smooth surface with a well-defined border, typical of the early stage of syphilis infection.

Secondary Stage of Syphilis

If syphilis is left untreated, it progresses to the secondary stage, typically 2 to 8 weeks after the initial chancre disappears. This stage is marked by a wide range of symptoms as the bacteria spread throughout the body.

A characteristic rash appears, often on the palms of the hands and soles of the feet.The rash can vary in appearance, but it’s often reddish-brown and may be scaly.Notably, this rash is not always itchy.

Other Symptoms associated with it includes, fever, fatigue, headache, sore throat, and swollen lymph nodes. These symptoms can be similar to those of other illnesses.

During this stage, you may develop highly contagious lesions, including condyloma lata (wart-like lesions) in moist areas.

The symptoms of secondary syphilis can disappear on their own, but without treatment, the infection will progress to the latent stage.It’s crucial to remember that even if the symptoms disappear, the infection is still present. If you experience any of these symptoms, especially a rash on your palms or soles, seek medical attention promptly.

Syphilis, secondary stage, raised, red, scaly plaques: This image shows the scalp and forehead with multiple raised, red, scaly plaques characteristic of secondary syphilis lesions. These plaques, located at the hairline and forehead, indicate the skin manifestations commonly seen during the secondary stage of syphilis.

Syphilis, secondary stage, raised, red, scaly plaques: This image shows the back of an individual with multiple raised, red, scaly plaques, which are typical lesions seen during the secondary stage of syphilis.

Latent Stage of Syphilis

Following the secondary stage, syphilis enters the latent stage, a period where all visible symptoms disappear. However, the infection remains in the body.

During the latent stage, individuals experience no noticeable symptoms. The latent stage can last for years or even decades.Without treatment, some individuals may relapse back into the secondary stage.Even without symptoms, syphilis remains contagious during the latent stage, and transmission through sexual contact is still possible.

Tertiary Stage (Late Syphilis) of Syphilis

If left untreated, syphilis can progress to the tertiary stage, which can occur years or even decades after the initial infection. Between 25% and 40% of individuals with untreated syphilis may develop tertiary syphilis. This stage is characterized by severe complications affecting various organ systems.

What you may notice?

This stage is also called the “destructive” stage because it can damage your organs. In this stage, you may develop

• Cardiovascular Syphilis: Can lead to aortic aneurysm and aortic valvulopathy.
• Neurosyphilis: Affects the nervous system, causing meningitis, stroke, seizures, and other neurological problems.Symptoms of neurosyphilis can include:
  • Headaches
  • Neck stiffness
  • Confusion
  • Ringing in the ears or hearing loss
  • Red, irritated eyes, blurry vision, or blindness
  • Stroke
  • Weakness
  • Dementia
  • Loss of balance

• Gummatous Syphilis: Involves the formation of gummas (soft, tumor-like growths) that can damage various organs.

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When it begins?

Reaching the tertiary stage of syphilis usually takes many years. However, syphilis can progress quickly. Without treatment, some people reach this last stage within 1 year of getting syphilis.

Even in this stage, treatment can stop the syphilis from getting worse. However, treatment cannot undo damage caused by syphilis.

It is important to tell your doctor if you have any of these symptoms. Neurosyphilis requires special treatment to cure it. You may need tests like an eye exam or other tests to tell if you have neurosyphilis.

Syphilis can also affect your eyes at any stage. Signs that this has happened include having red, irritated eyes and problems seeing clearly. Some people go blind.

Congenital Syphilis (Syphilis in Pregnancy and Newborns)

Congenital syphilis occurs when a pregnant person with syphilis passes the infection to their baby during pregnancy or childbirth. This can lead to serious health problems for the newborn, including stillbirth, premature birth, or low birth weight.

Pregnant individuals who use drugs or don’t receive prenatal care are at higher risk.There are also disparities among racial groups.Routine syphilis screening is recommended during pregnancy to prevent congenital syphilis.Early detection and treatment with penicillin during pregnancy is highly effective in preventing congenital syphilis.

Symptoms in Newborns

• Newborns may not show symptoms at birth, but can develop them later.
• Symptoms can include rashes, anemia, jaundice, and organ enlargement.
• Later in life if untreated, developmental problems can occur.

Testing and Diagnosis of Syphilis

Early detection of syphilis is essential for effective treatment and preventing long-term complications. Healthcare providers strongly recommend syphilis testing for individuals with STI symptoms, recent exposure, or those at high risk. Delayed testing can allow the infection to progress, leading to severe complications, including neurological, cardiovascular, and ocular damage.

How is Syphilis Diagnosed?

• A detailed medical history and physical examination help identify risk factors and potential symptoms of syphilis.
• Syphilis screening is recommended for:
  • Pregnant women (to prevent congenital syphilis).
  • Sexually active individuals at high risk (e.g., MSM, those with multiple partners, or HIV-positive individuals).
  • People who have had unprotected sex with a syphilis-infected partner.

Types of Syphilis Tests:

🔹 Primary Screening Tests:

• Nontreponemal Tests (RPR, VDRL)
  • Detects active infection by measuring antibodies against T. pallidum-induced damage.
  • Used for screening and monitoring treatment response.
  • Can produce false positives, so confirmation with a treponemal test is required.

🔹 Confirmatory Tests:

• Treponemal Tests (FTA-ABS, TPPA, TPHA, CIA, EIA)
  • Detect antibodies specific to T. pallidum.
  • Remain positive for life but do not indicate active infection.
  • Used for confirmation if a nontreponemal test is reactive.

🔹 Specialized Testing for Severe Cases:

• Neurosyphilis Diagnosis
  • If neurosyphilis is suspected (e.g., symptoms of meningitis, vision loss, stroke-like episodes), lumbar puncture for cerebrospinal fluid (CSF) analysis is necessary.
  • CSF tests may include VDRL, FTA-ABS, or PCR assays.

Are Home Syphilis Tests Reliable?

• FDA-approved at-home syphilis tests exist but are not widely available.
• These tests detect treponemal antibodies and can suggest past exposure.
• Any positive result requires confirmatory laboratory testing for accurate diagnosis.

Treatment and Follow-Up of Syphilis

Penicillin remains the cornerstone of syphilis treatment and is effective across all stages of the disease. Due to the slow replication rate of Treponema pallidum, longer-acting formulations such as benzathine penicillin G are preferred for most cases. However, neurosyphilis, ocular syphilis, and otic syphilis require aqueous crystalline penicillin G to ensure adequate cerebrospinal fluid (CSF) penetration.

Recommended Treatment Guidelines

• Primary, Secondary, and Early Latent Syphilis

  • A single intramuscular injection of 2.4 million units of benzathine penicillin G.

• Late Latent and Tertiary Syphilis (without neurosyphilis)

  • Three weekly injections of 2.4 million units of benzathine penicillin G (total of 7.2 million units).

• Neurosyphilis, Ocular Syphilis, and Otic Syphilis

  • Intravenous aqueous crystalline penicillin G (18–24 million units/day) for 10–14 days.
  • Alternative: Procaine penicillin G (2.4 million units IM daily) + Probenecid (500 mg orally four times daily) for 10–14 days.

Alternative Treatments

For patients with a penicillin allergy:

• Doxycycline (100 mg orally twice daily) for 14 days (primary & secondary syphilis) or 28 days (latent syphilis).
• Ceftriaxone (1–2 g IM/IV daily) for 10–14 days (used in neurosyphilis, but optimal dosing for syphilis is not well established).
• Azithromycin is no longer recommended due to increasing resistance.

Important Note: Pregnant individuals with syphilis must be treated with penicillin. If allergic, penicillin desensitization should be performed.

Follow-Up and Special Considerations

• Follow-up serologic testing (RPR or VDRL) at 6, 12, and 24 months to confirm treatment response.
• Neurosyphilis requires CSF testing every 6 months until normalization.
• HIV-positive individuals should be treated with the same regimen but require closer monitoring due to the risk of atypical disease progression.
• Sexual partners exposed within 90 days should be treated presumptively, even if their serologic test results are negative.
• Reinfection is possible, so continued safe sex practices and regular STI screening are advised.

Disclaimer:

This information is for educational purposes only and does not substitute professional medical advice, diagnosis, or treatment.

If you suspect you have syphilis, consult a healthcare provider for proper evaluation and treatment.

Preventing Syphilis and Practicing Safe Sex

Safe Sexual Practices

• Consistent condom use significantly reduces the risk of syphilis and other STIs.
• Open communication with sexual partners about STI testing is key to reducing transmission.

Regular Testing

• Annual syphilis screening is recommended for sexually active individuals.
• More frequent testing (every 3 to 6 months) is advised for:
  • Men who have sex with men (MSM)
  • Individuals with multiple partners
  • People with HIV
• Pregnant women should be tested as part of routine prenatal care to prevent congenital syphilis.

Post-Exposure Prevention

• If you have had unprotected sex with a known syphilis-infected partner, early medical evaluation and treatment may help prevent infection.
• A single dose of benzathine penicillin G may be given as a preventive measure in certain high-risk cases.

Self-Testing & Home Testing

• Home syphilis test kits offer a discreet and convenient option for early detection.
• Positive results must be confirmed by a healthcare provider to ensure accuracy and proper treatment.

Public Health & Future Prevention

• Partner notification and treatment are essential to prevent reinfection and break the transmission cycle.
• Ongoing vaccine research may offer a long-term solution to syphilis prevention.

When to Seek Medical Attention

If you notice a painless sore, rash, swollen lymph nodes, or flu-like symptoms, especially after unprotected sex, consult a doctor immediately. Syphilis is highly contagious and can cause serious long-term complications if left untreated.

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