Syphilis: A Comprehensive Guide

Overview

Syphilis is a bacterial infection usually spread by sexual contact. The disease starts as a painless sore — typically on your genitals, rectum or mouth. Syphilis spreads from person to person via skin or mucous membrane contact with these sores.

After the initial infection, the syphilis bacteria can remain inactive (dormant) in your body for decades before becoming active again. Early syphilis can be cured, sometimes with a single injection of penicillin. Without treatment, syphilis can severely damage your heart, brain or other organs, and can be life-threatening. Syphilis can also be passed from mothers to unborn children.

Who it affects: Syphilis can affect anyone who is sexually active. It's more common in people who have unprotected sex, have multiple sexual partners, or have sex with someone who has syphilis.

Prevalence: According to the Centers for Disease Control and Prevention (CDC), syphilis rates in the United States have been increasing. In 2019, there were over 129,000 reported cases of syphilis (all stages), with the rate of primary and secondary syphilis increasing by 11.2% from 2018.

Symptoms

Syphilis develops in stages, and symptoms vary with each stage. But the stages may overlap, and symptoms don’t always occur in the same order. You may be infected with syphilis and not notice any symptoms for years.

Primary syphilis

The first sign of syphilis is a small sore, called a chancre (SHANG-kur). The sore appears at the spot where the bacteria entered your body.

While most people infected with syphilis develop only one chancre, some people develop several of them. The chancre usually develops about three weeks after exposure. Many people who have syphilis don’t notice the chancre because it’s usually painless, and it may be hidden within the vagina or rectum. The chancre will heal on its own within three to six weeks.

Secondary syphilis

Within a few weeks of the original chancre healing, you may experience a rash that begins on your trunk but eventually covers your entire body — even the palms of your hands and the soles of your feet.

This rash is usually not itchy and may be accompanied by wart-like sores in the mouth or genital area. Some people also experience hair loss, muscle aches, fever, sore throat and swollen lymph nodes. These signs and symptoms may disappear within a few weeks or repeatedly come and go for as long as a year.

Latent syphilis

If you aren’t treated for syphilis, the disease moves from the secondary to the latent (hidden) stage, when you have no symptoms. The latent stage can last for years. Signs and symptoms may never return, or the disease may progress to the tertiary (third) stage.

Tertiary (late) syphilis

About 15% to 30% of people infected with syphilis who don’t get treatment will develop complications known as tertiary (late) syphilis. In the late stage, the disease may damage your brain, nerves, eyes, heart, blood vessels, liver, bones and joints. These problems may occur many years after the original, untreated infection.

Neurosyphilis and ocular syphilis

At any stage, syphilis can spread and, among other damage, cause problems with your nervous system (neurosyphilis), eyes (ocular syphilis) or ears (otosyphilis).

Congenital syphilis

Babies born to women who have syphilis can become infected through the placenta or during birth. Most newborns with congenital syphilis have no symptoms, although some experience a rash on the palms of their hands and the soles of their feet. Later signs and symptoms may include deafness, teeth deformities and saddle nose — where the bridge of the nose collapses.

However, babies born with syphilis can also be stillborn or die shortly after birth.

Causes and Risk Factors

Causes

The cause of syphilis is a bacterium called Treponema pallidum. The most common way syphilis is spread is through contact with an infected person's sore during sexual activity. The bacteria enter your body through minor cuts or abrasions in your skin or mucous membranes. Syphilis is contagious during its primary and secondary stages, and sometimes in the early latent period.

Less commonly, syphilis may spread through direct unprotected close contact with an active lesion (such as during kissing) or through an infected mother to her baby during pregnancy or childbirth (congenital syphilis). Syphilis can't be spread by using the same toilet, bathtub, clothing or eating utensils, or from doorknobs, swimming pools or hot tubs.

Risk factors

You face an increased risk of acquiring syphilis if you:

• Engage in unprotected sex
• Have sex with multiple partners
• Are a man who has sex with men
• Are infected with HIV, the virus that causes AIDS

Diagnosis

Syphilis can be diagnosed by testing samples of:

• Blood: Blood tests can confirm the presence of antibodies that the body produces to fight infection. The antibodies to the syphilis bacteria remain in your body for years, so the test can be used to determine a current or past infection.
• Fluid from sores: Your doctor may scrape a small sample of cells from a sore to be analyzed by microscope in a lab. This test can be done only during primary and secondary syphilis, when sores are present.
• Cerebrospinal fluid: If it's suspected that you have nervous system complications of syphilis, your doctor may also suggest collecting a sample of cerebrospinal fluid through a procedure called a lumbar puncture (spinal tap).

After a diagnosis of syphilis, it's recommended that you:

• Get tested for HIV infection
• Get tested for other sexually transmitted infections (STIs)
• Notify your sexual partners so that they can be tested and get treatment if necessary
• Abstain from sexual contact until the infection has been treated

Treatment Options

Medications

When diagnosed and treated in its early stages, syphilis is easy to cure. The preferred treatment at all stages is penicillin, an antibiotic medication that can kill the organism that causes syphilis. If you're allergic to penicillin, your doctor may suggest another antibiotic or recommend penicillin desensitization.

If you have neurosyphilis, you will need to receive intravenous penicillin daily for 10 to 14 days.

After treatment for syphilis, your doctor will ask you to:

• Have periodic blood tests and exams to make sure you're responding to the usual dosage of penicillin
• Avoid sexual contact with new partners until the treatment is completed and blood tests indicate the infection has been cured
• Notify your sex partners so that they can be tested and treated if necessary
• Get tested for HIV infection

Follow-up

After you're treated for syphilis, your doctor will ask you to:

• Have periodic blood tests and exams to make sure you're responding to the usual dosage of penicillin
• Avoid sexual contact with new partners until the treatment is completed and blood tests indicate the infection has been cured
• Notify your sex partners so that they can be tested and treated if necessary
• Get tested for HIV infection

Living with Syphilis

If you've been diagnosed with syphilis, it's important to follow your treatment plan and take all medications as prescribed. Here are some tips for managing syphilis:

• Complete the full course of antibiotics, even if symptoms disappear.
• Abstain from sexual activity until you and your partner(s) have completed treatment.
• Notify your sexual partners so they can be tested and treated if necessary.
• Get tested for other STIs, including HIV.
• Attend all follow-up appointments to ensure the infection is cured.
• Practice safe sex to prevent reinfection.

Prevention

There's no vaccine for syphilis. To help prevent the spread of syphilis, follow these suggestions:

• Abstain from sex or have mutually monogamous sex with an uninfected partner.
• Use a latex condom during sexual contact. Condoms can reduce your risk of getting syphilis, but only if the condom covers the syphilis sores.
• Avoid recreational drugs that might lead to risky sexual behavior.
• If you are pregnant and have syphilis, get treatment right away to prevent congenital syphilis in your baby.

If you are at high risk of syphilis (e.g., men who have sex with men, people with multiple sexual partners, or people with HIV), consider getting tested for syphilis regularly.

Complications

Without treatment, syphilis can lead to damage throughout your body. Syphilis also increases the risk of HIV infection and, for women, can cause problems during pregnancy. Treatment can help prevent future damage but can't repair or reverse damage that's already occurred.

Small bumps or tumors

Called gummas, these bumps can develop on your skin, bones, liver or any other organ in the late stage of syphilis. Gummas usually disappear after treatment with antibiotics.

Neurological problems

Syphilis can cause a number of problems with your nervous system, including:

• Stroke
• Meningitis
• Deafness
• Visual problems, including blindness
• Dementia
• Loss of pain and temperature sensations
• Sexual dysfunction in men (impotence)
• Bladder incontinence
• Sudden, lightning-like pains

Cardiovascular problems

These may include bulging (aneurysm) and inflammation of the aorta — your body's major artery — and other blood vessels. Syphilis may also damage heart valves.

HIV infection

Adults with sexually transmitted syphilis or other genital ulcers have an estimated 2- to 5-fold increased risk of acquiring HIV. A syphilis sore can bleed easily, providing an easy way for HIV to enter your bloodstream during sexual activity.

Pregnancy and childbirth complications

If you're pregnant, you may pass syphilis to your unborn baby. Congenital syphilis greatly increases the risk of miscarriage, stillbirth or your newborn's death within a few days after birth.

When to Seek Emergency Care

Sources and Further Reading

• Mayo Clinic
• Centers for Disease Control and Prevention (CDC)
• National Institutes of Health (NIH)
• World Health Organization (WHO)
• Cleveland Clinic