Syphilis is a sexually transmitted disease (STD) caused by the bacterium Treponema pallidum. It has often been called “the great imitator” because so many of the signs and symptoms are indistinguishable from those of other diseases.

An ancient disease, syphilis is still of major importance today. In 2008 13,500 cases were reported in the United States, mostly in people 20-29 years of age. Of these reported cases, 63% were among men who have sex with men. Syphilis rates have increased in males each year between 200 and 2008 and in females each year between 200 and 2008.

Causes and Symptoms

A reported 36,000 syphilis cases occurred in the United States in 2006.

Syphilis is a sexually transmitted bacterial infection that causes genital ulcers (painless sores) in it’s early stages. If untreated these ulcers can lead to more serious symptoms of infection.

Without treatment, syphilis in adults progresses through four stages: primary, secondary, latent, and tertiary.


How do people get syphilis?

Syphilis is passed from person to person through direct contact with a syphilis sore. Sores occur mainly on the external genitals, vagina, anus, or in the rectum. Sores also can occur on the lips and in the mouth. Transmission of the organism occurs during vaginal, anal, or oral sex. Pregnant women with the disease can pass it to the babies they are carrying. Syphilis cannot be spread through contact with toilet seats, doorknobs, swimming pools, hot tubs, bathtubs, shared clothing, or eating utensils.

Persons with syphilis are most infectious during the primary and secondary stages. Primary syphilis is marked by an infectious sore (chancre) that resolves on its own. Without treatment, syphilis bacteria spread through the bloodstream and lead to the secondary stage, which is characterized by a skin rash and systemic symptoms.

These symptoms can come and go over one to two years, during which an infected person can infect others. If untreated, the infection progresses to a latent stage. Symptoms disappear, and the disease is no longer infectious, but the bacteria remain in the body and can damage vital organs.

In about a third of untreated persons, the results of the internal damage show up years later in the tertiary stage. Symptoms include paralysis, blindness, dementia, impotence, joint damage, heart problems, tumors, and deep sores. The damage can be serious enough to cause death.

An untreated pregnant woman in an infectious stage of syphilis can pass the infection to her developing fetus.


It can be very difficult for your healthcare provider to diagnose syphilis based on symptoms. This is because symptoms and signs of the disease might be absent, go away without treatment, or be confused with those of other diseases. Because syphilis can be hard to diagnose, you should:

  • Visit your healthcare provider if you have a lesion (sore) in your genital area or a widespread rash
  • Get tested periodically for syphilis if your sexual behaviors put you at risk for sexually transmitted diseases (STDs)
  • Get tested to be sure you don’t also have syphilis if you have been treated for another STD such as gonorrhea or HIV infection

Laboratory Tests

Your healthcare provider can diagnose early syphilis by seeing a chancre or rash and then confirming the diagnosis with laboratory tests. Because latent syphilis has no symptoms, it is diagnosed only by laboratory tests.

There are two methods for diagnosing syphilis through a laboratory.

  • Identifying the bacteria under a microscope in a sample of tissue (a group of cells) taken from a chancre
  • Performing a blood test for syphilis

If your healthcare provider thinks you might have neurosyphilis, your spinal fluid will be tested as well.


Syphilis is easy to cure in its early stages. Penicillin, an antibiotic, injected into the muscle, is the best treatment for syphilis. If you are allergic to penicillin, your healthcare provider may give you another antibiotic to take by mouth.

If you have neurosyphilis, you may need to get daily doses of penicillin intravenously (in the vein) and you may need to be treated in the hospital.

If you have late syphilis, damage done to your body organs cannot be reversed.

While you are being treated, you should abstain from sex until any sores are completely healed. You should also notify your sex partners so they can be tested for syphilis and treated if necessary.

How Can Syphilis Be Prevented?

To prevent getting syphilis, you must avoid contact with infected tissue (a group of cells) and body fluids of an infected person. However, syphilis is usually transmitted by people who have no sores that can be seen or rashes and who do not know they are infected.

If you aren’t infected with syphilis and are sexually active, having mutually monogamous sex with an uninfected partner is the best way to prevent syphilis.

Using condoms properly and consistently during sex reduces your risk of getting syphilis.

Washing or douching after sex won’t prevent syphilis.

Even if you have been treated for syphilis and cured, you can be re-infected by having sex with an infected partner.

The risk of a mother transmitting syphilis to her unborn baby during pregnancy declines with time but persists during latent syphilis. To prevent passing congenital syphilis to their unborn babies, all pregnant women should be treated for syphilis.



Syphilis can cause miscarriages, premature births, or stillbirths. It can also cause death of newborn babies. Some infants with congenital syphilis have symptoms at birth, but most develop symptoms later.

Untreated babies with congenital syphilis can have deformities, delays in development, or seizures, along with many other problems such as rash, fever, swollen liver and spleen, anemia, and jaundice. Sores on infected babies are infectious. Rarely, the symptoms of syphilis may go unseen in infants and they develop the symptoms of late-stage syphilis, including damage to their bones, teeth, eyes, ears, and brains.

HIV infection

People infected with syphilis have a two- to five-fold increase risk of getting infected the HIV. Strong evidence shows the increased odds of getting and transmitting HIV in the presence of sexually transmitted diseases (STDs). You should discuss this and other STDs with your healthcare provider.



Centers for Disease Control and Prevention Syphilis Fact Sheet – 2011,

NIAID – STD Syphilis,