Syphilis is a bacterial infection usually spread by sexual contact. The disease starts as a painless sore — typically on the 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 in the body for decades before becoming active again. Early syphilis can be cured, sometimes with a single shot (injection) of penicillin.

Without treatment, syphilis can severely damage the heart, brain or other organs, and can be life-threatening. Syphilis can also be passed from mothers to unborn children.

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 without noticing 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 wartlike sores in your mouth or genital area. Some people also experience hair loss, muscle aches, a fever, a 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 stage to the hidden (latent) 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 third (tertiary) stage.

Tertiary syphilis

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

Neurosyphilis

At any stage, syphilis can spread and, among other damage, cause damage to the brain and nervous system and the eye.

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 born too early, may die in the womb before birth or can die after birth.

When to see a doctor

Call your doctor if you or your child experiences any unusual discharge, sore or rash — particularly if it occurs in the groin area.

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 the body through minor cuts or abrasions in the 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 contact with an active lesion, such as during kissing. It can also be passed from mothers to their babies during pregnancy or childbirth.

Syphilis can't be spread by using the same toilet, bathtub, clothing or eating utensils, or from doorknobs, swimming pools or hot tubs.

Once cured, syphilis doesn't return on its own. However, you can become reinfected if you have contact with someone's syphilis sore.

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

Without treatment, syphilis can lead to damage throughout your body. Syphilis also increases the risk of HIV infection and 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

In the late stage of syphilis, bumps (gummas) can develop on the skin, bones, liver or any other organ. Gummas usually disappear after treatment with antibiotics.

Neurological problems

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

• Headache
• Stroke
• Meningitis
• Hearing loss
• Visual problems, including blindness
• Dementia
• Loss of pain and temperature sensations
• Sexual dysfunction in men
• Bladder incontinence

Cardiovascular problems

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

HIV infection

Adults with sexually transmitted syphilis or other genital ulcers have an estimated two- to fivefold increased risk of contracting HIV. A syphilis sore can bleed easily, providing an easy way for HIV to enter the 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.

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

• Abstain or be monogamous. The only certain way to avoid syphilis is to avoid (abstain from) having sex. The next-best option is to have mutually monogamous sex in which both partners have sex only with each other and neither partner is infected.
• Use a latex condom. Condoms can reduce your risk of contracting syphilis, but only if the condom covers the syphilis sores.
• Avoid recreational drugs. Misuse of alcohol or other drugs can inhibit your judgment and lead to unsafe sexual practices.

Partner notification and preventive treatment

If tests show that you have syphilis, your sex partners — including current partners and any other partners you've had over the last three months to one year — need to be informed so that they can get tested. If they're infected, they can then be treated.

Official, confidential partner notification can help limit the spread of syphilis. The practice also steers those at risk toward counseling and the right treatment. And since you can contract syphilis more than once, partner notification reduces your risk of getting reinfected.

Screening for pregnant women

People can be infected with syphilis and not know it. In light of the often deadly effects syphilis can have on unborn children, health officials recommend that all pregnant women be screened for the disease.

Tests

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-causing bacteria remain in your body for years, so the test can be used to determine a current or past infection.
• 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 lumbar puncture.

Through the Centers for Disease Control and Prevention, your local health department offers partner services, which will help you notify your sexual partners that they may be infected. Your partners can be tested and treated, limiting the spread of syphilis.

Medication

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.

The recommended treatment for primary, secondary or early-stage latent syphilis — which refers to an infection within the last year — is a single injection of penicillin. If you've had syphilis for longer than a year, you may need additional doses.

Penicillin is the only recommended treatment for pregnant women with syphilis. Women who are allergic to penicillin can undergo a desensitization process that may allow them to take penicillin.

Even if you're treated for syphilis during your pregnancy, your newborn child should be tested for congenital syphilis and if infected, receive antibiotic treatment.

The first day you receive treatment, you may experience what's known as the Jarisch-Herxheimer reaction. Signs and symptoms include a fever, chills, nausea, achy pain and a headache. This reaction usually doesn't last more than one day.

Treatment 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. Your specific follow-up will depend on the stage of syphilis you're diagnosed with.
• 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 get treatment if necessary.
• Be tested for HIV infection.

Finding out you have syphilis can be extremely upsetting. You might experience anger if you feel you've been betrayed, or shame if you think you've infected others.

However, hold off placing blame. Don't assume that your partner has been unfaithful to you. One (or both) of you may have been infected by a past partner.

Most people don't feel comfortable sharing the details of their sexual experiences, but the doctor's office is one place where you have to provide this information so that you can get the right care.

What you can do

• Be aware of any pre-appointment restrictions. At the time you make the appointment, ask if there's anything you need to do in advance.
• Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
• Make a list of all medications, vitamins or supplements you're taking.
• Write down questions to ask your doctor.

Some basic questions to ask your doctor include:

• What's the medical name of the infection I have?
• How is it transmitted?
• Will it keep me from having children?
• If I get pregnant, could I give it to my baby?
• Is it possible to catch this again?
• Could I have caught this from someone I had sex with only once?
• Could I give this to someone by having sex with that person just once?
• How long have I had it?
• I have other health conditions. How can I best manage them together?
• Should I avoid sexual activity while I'm being treated?
• Does my partner have to go to a doctor to be treated?

What to expect from your doctor

Giving your doctor a complete report of your symptoms and sexual history will help your doctor determine how to best care for you. Here are some of the things your doctor may ask:

• What symptoms made you decide to come in? How long have you had these symptoms?
• Are you sexually active with men, women or both?
• Do you currently have one sex partner or more than one?
• How long have you been with your current partner or partners?
• Have you ever injected yourself with drugs?
• Have you ever had sex with someone who has injected drugs?
• What do you do to protect yourself from sexually transmitted infections (STIs)?
• What do you do to prevent pregnancy?
• Has a doctor or nurse ever told you that you have chlamydia, herpes, gonorrhea, syphilis or HIV?
• Have you ever been treated for a genital discharge, genital sores, painful urination or an infection of your sex organs?
• How many sex partners have you had in the past year? In the past two months?
• When was your most recent sexual encounter?

What you can do in the meantime

If you think you might have syphilis, it's best to avoid sex until you've talked with your doctor. If you do engage in sexual activity before seeing your doctor, be sure to follow safe sex practices, such as using a condom.