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Syphilis Symptoms

Contributor Kevin Ard, MD
5 minute read
A happy couple poses for a photo outdoors, with the woman hugging the man from behind.

Syphilis is one of the most common sexually transmitted infections (STIs) in the United States. It can cause serious health problems if not treated. Despite access to a cure, syphilis cases have increased by more than 50% in the United States since 2016.

“People can spread the disease without noticing their own symptoms, or when the infection is in an asymptomatic phase,” says Kevin Ard, MD, a Mass General Brigham infectious diseases doctor.

Dr. Ard is the director of the Sexual Health Clinic at Massachusetts General Hospital. He describes how syphilis spreads and gives tips on ways to prevent infection. Learn how to recognize syphilis symptoms and find treatment.

What is syphilis?

Syphilis is an infection that can spread from one person to another through sex. Bacteria from the disease spreads easily from person to person. Sores develop where bacteria enter the body, often on the penis, vagina, mouth, and tongue. Unlike herpes, the sores are not often painful. They can take weeks for patients to notice.

Stages of syphilis

Syphilis typically follows a progression of stages that can last for weeks, months, or years. There are 3 stages, and the condition spreads easiest during the first 2.

Primary stage

The first stage, or primary stage, typically begins 3 weeks after the disease first enters the body. It can take 3 to 4 weeks for small, round sores — called “chancres” — to appear on the skin. Chancres stay on the skin for 2 to 6 weeks and can go away without treatment.

Secondary stage

Sores from syphilis in its secondary stages can appear on the hands. Source: Centers for Disease Control and Prevention

The second stage, or secondary stage, causes a wide range of symptoms. The most common is a skin rash. The rash can form anywhere on the body, but it most often forms on the hands and feet.

Other symptoms include:

  • Fever

  • Sore throat

  • Headaches

  • Fatigue

  • Weight loss

  • Swollen neck (lymph nodes)

  • Hair loss

  • Aching joints

“Patients often mistake the symptoms of syphilis for common diseases and other STIs, such as mpox,” says Dr. Ard. “That’s why doctors call it the ‘great imitator.’”

Latent syphilis

Syphilis can affect the brain at any stage, potentially leading to meningitis, hearing problems, and difficulty seeing. It can persist for years, sometimes without any noticeable symptoms. When no visible signs or symptoms occur, syphilis has entered a latent, or hidden, stage.

Even during this latent stage, syphilis bacteria remain in the body. They remain there until treatment occurs.

Tertiary stage

If left untreated, syphilis can develop into a third, final stage.

Complications at this stage include:

  • Heart problems, including aorta dilation and associated dysfunction of the aortic valve

  • Neurological problems

  • Tumors

These symptoms can develop into:

  • Brain damage

  • Blindness

  • Paralysis

  • Death

Patients often mistake symptoms of syphilis for common diseases and other STIs, such as mpox. That’s why doctors call it the ‘great imitator.’

Kevin Ard, MD
Infectious Diseases Doctor
Mass General Brigham

How is syphilis diagnosed?

Health care providers use a blood test to diagnose syphilis. If they suspect the condition has affected the brain, they check a patient’s spinal fluid as well.

Who should be tested?

If you’re sexually active, get screened for syphilis. Screenings are simple and painless.

STI screening in pregnancy is especially important because STIs can lead to pregnancy complications and have serious effects on a baby’s health. Syphilis increases the risk of an unborn baby dying. People who are pregnant can unknowingly pass the disease to their child. According to the Centers for Disease Control and Prevention (CDC), such cases have increased dramatically since 2012. A decline in condom use helps explain why.

Syphilis medication

Health care providers use medication to treat syphilis. A single injection of the drug penicillin can kill bacteria responsible for the condition at the first and second disease stage. Patients in the third disease stage need at least 3 injections spread several weeks apart. Alternative drugs exist for patients who are allergic to penicillin.

Unfortunately, no drug can reverse damage to the eyes, ears, and brain. Syphilis also increases the risk of developing HIV. Open sores on the genitals allow HIV to spread from the blood of one person to another.

People with syphilis should pause all sexual activity until they have completed treatment. They can still pass the disease to others until they are fully treated.

Is syphilis preventable?

According to Dr. Ard, the best treatment for syphilis is prevention. To avoid syphilis, he encourages people to:

  • Wear condoms.

  • Choose fewer sex partners.

  • Undergo regular STI screenings.

The CDC and health care providers are also reviewing a cutting-edge strategy called Doxy PEP, which could help prevent the spread of syphilis. The strategy involves taking an antibiotic pill after sex to help prevent infection.

“We are hopeful that a vaccine for syphilis will one day be available,” Dr. Ard adds. “Until then, we must continue to be vigilant and prevent syphilis in other ways.”

Kevin Ard, MD


Infectious Diseases Doctor