Causes

Syphilis is a sexually transmitted, infectious disease caused by the spirochete Treponema pallidum. This bacterium causes infection when it gets into broken skin or mucus membranes, usually of the genitals. Syphilis 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 areas, and the number of cases is rising fastest 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 should be screened for syphilis to prevent the infection from passing to their newborn (congenital syphilis).

Syphilis has three stages:

• Primary syphilis
• Secondary syphilis
• Tertiary syphilis (the late phase of the illness)

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-sponsored sexually transmitted disease clinics
• Screening tests for syphilis
• Public education about STDs
• Prenatal screening

Symptoms

Primary syphilis symptoms include:

• Chancre -- a small, painless open sore or ulcer on the genitals, mouth, skin, or rectum that heals 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 are few symptoms until the second stage.

Secondary syphilis symptoms include:

• A skin rash (the most common symptom), which often involves the palms of the hands and soles of the feet. Sores called mucous patches may develop in or around the mouth, vagina, or penis.
• Moist, warty patches may develop in the genitals or skin folds. These are called condylomata lata.
• Other symptoms, such as fever, general ill feeling, loss of appetite, muscle aches, joint pain, enlarged lymph nodes, vision changes, and hair loss may occur.

Symptoms of tertiary syphilis depend on which organs have been affected. They vary widely and are difficult to diagnose. Symptoms of tertiary syphilis include:

• Cardiovascular syphilis, which affects the aorta of the heart and causes aneurysms or valve disease
• Central nervous system disorders (neurosyphilis)
• Tumors of skin, bones, or liver (gumma)

Exams and Tests

• Dark field examination of fluid from sore
• Echocardiogram, aortic angiogram, and cardiac catheterization to look at the major blood vessels and the heart
• Serum RPR or serum VDRL (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
• Spinal fluid examination

Treatment

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 how severe the syphilis is, and factors such as the patient's overall health.

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

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

Symptoms and signs of this reaction include:

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

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.

Outlook (Prognosis)

Syphilis can be cured if it is diagnosed early and completely treated.

Secondary syphilis can be cured if it is diagnosed early and treated effectively. Although it usually goes away within weeks, in some cases it may last for up to 1 year. Without treatment, up to one-third of patients will have late complications of syphilis.

Late syphilis may be permanently disabling, and it may lead to death.

Possible Complications

• Cardiovascular complications (aortitis and aneurysms)
• Destructive sores of skin and bones (gummas)
• Neurosyphilis
• Syphilitic myelopathy - a complication that involves muscle weakness and abnormal sensations
• Syphilitic meningitis

In addition, untreated secondary syphilis during pregnancy may spread the disease to the developing baby. This is called congenital syphilis.

When to Contact a Medical Professional

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.

Prevention

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

All pregnant women should be screened for syphilis.

Alternative Names

Primary syphilis; Secondary syphilis; Late syphilis; Tertiary syphilis

References

Centers for Disease Control and Prevention (CDC). Recommendations and Reports: Sexually Transmitted Diseases. MMWR Morb Mortal Wkly Rep. 2006;55(RR-11).

Screening for syphilis infection in pregnancy: U.S. Preventive Services Task Force reaffirmation recommendation statement. Ann Intern Med. 2009;150:705-709.

Screening for syphilis infection. Topic Page. July 2004. U.S. Preventive Services Task Force. Agency for Healthcare Research and Quality, Rockville, MD. Accessed 6/28/2010.

Tramont EC. Traponema pallidum (syphilis). In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 238.

Updated: 4/30/2012

Reviewed by: Linda Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington School of Medicine; and Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School, Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.