Syphilis

What Is Syphilis?

Syphilis is a sexually transmitted infection (STI) caused by the bacterium Treponema pallidum. It spreads primarily through direct contact with a syphilitic sore (called a chancre) during vaginal, anal, or oral sex. The infection can also be passed from a pregnant person to their baby during pregnancy or childbirth, a condition known as congenital syphilis.

If left untreated, syphilis can progress through several stages and cause serious, long-term damage to the heart, brain, nervous system, and other organs. Early detection and treatment are essential to prevent complications.

Is Syphilis Curable?

Yes, syphilis is curable with appropriate antibiotics, typically penicillin. Treatment is highly effective when started early, but the type and duration of therapy depend on the stage of the infection. Antibiotics can eliminate the bacteria at any stage, but they cannot reverse damage that has already occurred in advanced cases.Because reinfection is possible, ongoing prevention and regular testing remain important even after successful treatment.

Stages and Symptoms of Syphilis

Syphilis progresses in stages, and symptoms can vary widely. Some people experience no symptoms for long periods, and the infection is sometimes called “The Great Pretender” because its signs can resemble other conditions. Stages may overlap or skip, and sores can appear in areas that are not easily visible.

Primary Syphilis

The first sign is usually a single (sometimes multiple) painless sore called a chancre. It appears at the site where the bacteria entered the body — often on or around the genitals, anus, rectum, lips, or mouth. Chancres typically develop 10–90 days after exposure (average 3 weeks) and heal on their own within 3–6 weeks. Even after the sore disappears, the bacteria remain in the body without treatment.

Secondary Syphilis

This stage often begins while the chancre is healing or weeks after it has gone away. Symptoms may include:

• A non-itchy skin rash (often on the palms of the hands or soles of the feet)
• Mucous membrane lesions in the mouth, vagina, or anus
• Fever
• Swollen lymph nodes
• Sore throat
• Headache
• Muscle aches
• Fatigue
• Hair loss
• Weight loss

These symptoms may resolve without treatment, but the infection remains active and can progress if not treated.

Latent Syphilis

In this stage, there are no visible symptoms, sometimes for years. The bacteria are still present in the body. During early latent syphilis, a person can still transmit the infection to sexual partners.

Tertiary Syphilis

This late stage occurs in some untreated cases and can develop many years after initial infection. It can cause severe damage, including:

• Gummas (soft, destructive lesions on the skin or inside the body)
• Heart and blood vessel problems
• Neurological issues (neurosyphilis), such as strokes, numbness, or changes in mental status
• Vision problems or blindness
• Bone pain

Neurosyphilis and ocular syphilis can occur at any stage of the infection.

How Is Syphilis Transmitted?

Syphilis is most commonly spread through direct skin-to-skin or mucous membrane contact with a chancre during sexual activity. It is contagious mainly during the primary and secondary stages, and sometimes during early latent syphilis.

Congenital syphilis occurs when the bacteria pass from a pregnant person to the fetus. Untreated syphilis during pregnancy can lead to serious outcomes for the baby, including stillbirth or newborn complications. Routine prenatal screening helps reduce this risk.Syphilis is not spread through casual contact such as hugging, sharing utensils, or toilet seats.

Who Is at Higher Risk?

Anyone who is sexually active can contract syphilis. Risk may be higher for individuals who:

• Have unprotected sex
• Have multiple sexual partners
• Have a partner diagnosed with syphilis
• Are men who have sex with men (MSM)
• Have HIV

The CDC recommends syphilis testing for all pregnant individuals at their first prenatal visit, with additional testing in some cases based on risk.

How to Prevent Syphilis

The most reliable way to avoid syphilis is to abstain from sexual activity. For those who are sexually active, risk can be lowered by:

• Using latex or polyurethane condoms or dental dams correctly and consistently during vaginal, anal, or oral sex (note that condoms may not cover all sores)
• Being in a mutually monogamous relationship with a partner who has tested negative for STIs
• Limiting the number of sexual partners
• Having open conversations with partners about sexual health and testing
• Getting tested regularly if you are at increased risk

If you or a partner may have been exposed, get tested promptly and avoid sexual contact until cleared.

Important Note

This information is for general educational purposes only and is not a substitute for professional medical advice. Syphilis symptoms can be subtle or absent, so regular screening is key for sexually active individuals. 

If you have concerns about syphilis or any STI, consult a qualified healthcare provider for testing, diagnosis, and treatment. Early intervention is the best way to protect your health and prevent complications.

Resources

• CDC – Syphilis Fact Sheet: https://www.cdc.gov/syphilis/about/index.html
• CDC STI Treatment Guidelines: https://www.cdc.gov/std/treatment-guidelines/syphilis.htm
• CDC – Congenital Syphilis: https://www.cdc.gov/syphilis/about/congenital-syphilis.html
• CDC Screening Recommendations: https://www.cdc.gov/std/treatment-guidelines/screening-recommendations.htm