Syphilis is an easily spread infection caused by the bacteria Treponema pallidum.

Syphilis is an infectious disease. The bacteria that causes it spreads through broken skin or mucous membranes. It is most often spread by sexual contact.

Pregnant mothers infected with the disease can pass it to the baby developing in their womb. This is called congenital syphilis.

Syphilis is widespread in the United States. It mainly involves sexually active adults between ages 20 to 29.

Syphilis has several stages.

Primary syphilis is the first stage. Painless sores ( chancres ) form about 2-3 weeks after you are first infected. You may not notice the sores or any symptoms, particularly if the sores are inside the rectum or cervix. The sores disappear in about 4-6 weeks. For more specific information about this type of syphilis, see primary syphilis.

Secondary syphilis occurs about 2-8 weeks after the first sores form. About 33% of those who do not have primary syphilis treated will develop this second stage. For more specific information about this type of syphilis, see secondary syphilis.

Tertiary syphilis is the final stage of syphilis. The infection spreads to the brain, nervous system, heart, skin, and bones. For more specific information about this type of syphilis, see tertiary syphilis.

The symptoms of syphilis depend on the stage of the disease. Many people do not have symptoms.

In general, painless sores and swollen lymph nodes are symptoms of primary syphilis. Those with secondary syphilis may also have fever, fatigue, aches and pains, and loss of appetite, among other symptoms. Tertiary syphilis causes heart, brain, and nervous system problems.

For more information, see the article on the specific stage of syphilis.

Blood tests can be done to detect substances produced by the bacteria that causes syphilis. The older test is the VDRL test. Other blood tests may include RPR and FTA-ABS.

Antibiotics are used to treat syphilis. The antibiotic of choice is penicillin, yet doxycycline may be used as an alternative in individuals with a penicillin allergy.

The penicillin is either injected into a muscle or vein, depending on what stage syphilis you have.

Several hours after treatment of early stages of syphilis, you may have a reaction called Jarish-Herxheimer reaction. Symptoms of this reaction include:

• Fever
• Chills
• Headache
• Nausea
• General feeling of being ill
• General joint aches
• Genera muscle aches

These symptoms usually disappear within 24 hours.

You must have follow-up blood tests at 3, 6, 12, and 24 months to make sure the infection is gone. You should avoid sexual conduct until two follow-up tests show that the infection has been cured. Syphilis is extremely contagious in the primary and secondary stages.

Syphilis is a reportable infection -- that means that doctors must reported any cases of syphilis to public health authorities, so that potentially infected sexual partners may be identified and treated.

With prompt treatment and follow-up care, syphilis can be cured.

Late-stage syphilis can lead to long-term health problems, despite therapy.

Complications of untreated syphilis include:

• Neurosyphilis
• Heart and blood vessel problems, including aneurysms and inflammation of the aorta
• Damage to the skin and bones

Notify your health care provider if you develop signs or symptoms of syphilis. Several conditions may have similar symptoms, so you will need to have a complete medical exam.

Also call your health care provider for an appointment if you have had sexual contact with someone who has syphilis.

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

All pregnant women should be screened for syphilis.

Mandell GL, Bennett JE, Dolin R. Principles and Practice of Infectious Diseases. 6th ed. London: Churchill Livingstone; 2005:2274-2276.