Syphilis is a frequently diagnosed sexually transmitted disease.

Syphilis is a sexually transmitted, infectious disease caused by the spirochete Treponema pallidum. This bacteria causes infection when it gets into broken skin or mucus membranes, usually of the genitals. It is most often transmitted through sexual contact, although it also can be transmitted in other ways.

Syphilis occurs worldwide. Syphilis is more common in urban, rather than rural, areas, and the number of cases is rising most rapidly in men who have sex with men. Young adults, ages 15-25, are the highest-risk population. People have no natural resistance to syphilis.

Because people may be unaware that they are infected with syphilis, many states require tests for syphilis before marriage. All pregnant women who receive prenatal care are screened for syphilis to prevent the syphilis infection from passing from the mother to the newborn (congenital syphilis).

Syphilis has three stages:

• Primary syphilis
• Secondary syphilis
• Tertiary syphilis

Secondary syphilis, tertiary syphilis, and congenital syphilis are not seen as often in the United States as they were in the past because of the availability of free, government-run sexually transmitted disease clinics, screening tests for syphilis, public education about STDs, and prenatal screening.

Primary syphilis symptoms include:

• Chancre -- a small, painless open sore or ulcer on the genitals, mouth, skin, or rectum that should heal by itself in 3-6 weeks
• Enlarged lymph nodes in the area containing the chancre

The bacteria continue to multiply in the body, but there is little outward evidence of disease until the second stage.

• Dark field examination of fluid from sore
• SerumRPR or serumVDRL (used as screening tests to detect syphilis infection -- if positive, one of the following tests will be needed to confirm the diagnosis:)
  • FTA-ABS (fluorescent treponemal antibody test)
  • MHA-TP

Syphilis can be treated with antibiotics, such as penicillin G benzathine, doxycycline, or tetracycline (for patients who are allergic to penicillin). Length of treatment depends on the extent of the syphilis and factors such as the patient's overall health.

For treatment of syphilis during pregnancy, penicillin is the drug of choice. Tetracycline cannot be used because it is dangerous to the fetus, and erythromycin may not prevent congenital syphilis in the fetus. People who are allergic to penicillin should ideally be desensitized to it, then treated with penicillin.

Several hours after getting treatment for the early stages of syphilis, people may experience Jarish-Herxheimer reaction, which is caused by an immune reaction to the breakdown products of the infection.

Symptoms of this reaction include:

• Chills
• Fever
• General feeling of being ill (malaise)
• Headache
• Joint aches
• Muscle aches
• Nausea

These symptoms usually disappear within 24 hours.

Follow-up blood tests must be done at 3, 6, 12, and 24 months to ensure that the infection is gone. Avoid sexual contact when the chancre is present, and use condoms until two follow-up tests have indicated that the infection has been cured.

All sexual partners of the person with syphilis should also be treated. Syphilis is extremely contagious in the primary and secondary stages.

Syphilis can be completely cured if diagnosed early and treated thoroughly.

• Cardiovascular syphilis
• Congenital syphilis
• Neurosyphilis
• Secondary syphilis
• Syphilitic meningitis
• Tertiary syphilis

Call for an appointment with your health care provider if you have symptoms of syphilis.

If you have had intimate contact with a person who has syphilis or any other STD, or have engaged in any high-risk sexual practices, including having multiple or unknown partners or using intravenous drugs, contact your doctor or get screened in an STD clinic.

If you are sexually active, practice safe sex and always use a condom.

All pregnant women should be screen for syphilis.

U.S. Preventive Services Task Force. Screening for Syphilis Infection: Recommendation Statement. Ann Fam Med. 2004;2:362-365.

Tremont EC. Treponema pallidum (Syphilis). In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 6th ed. Philadelphia, Pa: Churchill Livingstone Elsevier; 2005: chap 235.