Syphilis is caused by the bacterium Treponema pallidum, and has often been called "the great imitator" because so many of its signs and symptoms are indistinguishable from those of other diseases. 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, but may also occur on the lips and in the mouth. Transmission of the organism occurs during vaginal, anal or oral sex.
Syphilis causes disease in three stages.
The time between infection with syphilis and the onset of symptoms can range from 10 to 90 days, with an average of 21 days. The primary stage of syphilis is usually marked by the appearance of a single sore called a chancre, but multiple sores may be present. The chancre is usually firm, round, small, and painless, and appears at the spot where syphilis entered the body. A chancre typically lasts three to six weeks and will heal on its own. If adequate treatment is not administered, the infection will progress to the secondary stage.
The second stage starts when one or more areas of the skin break into a rash that typically does not itch. Rashes may appear as the chancre is fading, or their onset can be delayed for weeks. The rash often appears as rough, red or reddish-brown spots both on the palms of the hands and the bottoms of the feet. The rash may also appear on other parts of the body with different characteristics. Sometimes the rashes are so faint that they go unnoticed, and even without treatment they clear up on their own. In addition to rashes, second-stage symptoms may include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches and fatigue. A person can easily pass the disease to sex partners when primary or secondary stage symptoms are present.
The latent (hidden) stage of syphilis begins when the secondary symptoms disappear. Without treatment, the infected person still has syphilis even though there are no signs or symptoms. It remains in the body and it may begin to damage the internal organs, including the brain, nerves, eyes, heart, blood vessels, liver, bones and joints. This internal damage may show up many years later in the late or tertiary stage of syphilis. Late stage signs and symptoms include not being able to coordinate muscle movements, paralysis, numbness, gradual blindness and dementia. This damage may be serious enough to cause death.
Pregnant women with syphilis can pass it on to their babies. Depending on how long a pregnant woman has been infected, she has a good chance of having a stillbirth (syphilitic stillbirth) or of giving birth to a baby who dies shortly afterward. An infected baby may be born and be asymptomatic, but he or she could develop very serious symptoms within a few weeks. These symptoms may cause untreated babies to become developmentally delayed, have seizures or die.
A health care provider can diagnose syphilis by using dark field microscopy to examine material from infectious sores. If syphilis bacteria are present in the sore, they will show up with a characteristic appearance. A blood test is another way to determine whether someone has syphilis. Shortly after infection occurs, the body produces syphilis antibodies that can be detected by a safe, accurate and inexpensive blood test. A low level of antibodies will remain in the blood for months-or even years-after the disease has been successfully treated. In the United States, health officials reported more than 35,600 cases of syphilis in 1999, including 6,650 cases of primary and secondary syphilis and 556 cases of congenital syphilis in newborns. Syphilis occurred primarily in people ages 20 to 39, and the reported rate in men was 1.5 times greater than the rate in women. The incidence of syphilis was highest in women aged 20 to 29 years and in men 30 to 39. Several fundamental societal problems such as poverty, inadequate access to health care and lack of education are associated with disproportionately high levels of syphilis in certain populations (e.g., African-Americans).
Syphilis is curable by treatment with penicillin (or other antibiotics in penicillin-allergic people). Penicillin treatment will kill the syphilis bacteria and prevent further damage, but it will not repair any damage already done. Persons who receive syphilis treatment must abstain from sexual contact with new partners until the syphilis sores are completely healed.
Genital sores caused by syphilis in adults also make it easier to sexually transmit and acquire HIV infection. There is a two- to fivefold increased risk of acquiring HIV infection when syphilis is present. Syphilis Fact Sheet (CDC)