Syphilis is a sexually transmitted disease caused by bacteria. It infects the genital area, lips, mouth, or anus of both men and women. You usually get syphilis from sexual contact with someone who has it. It can also pass from mother to baby during pregnancy.
The early stage of syphilis usually causes a single, small, painless sore. Sometimes it causes swelling in nearby lymph nodes. If you do not treat it, syphilis usually causes a non-itchy skin rash, often on your hands and feet. Many people do not notice symptoms for years. Symptoms can go away and come back.
The sores caused by syphilis make it easier to get or give someone HIV during sex. If you are pregnant, syphilis can cause birth defects, or you could lose your baby. In rare cases, syphilis causes serious health problems and even death.
Syphilis is easy to cure with antibiotics if you catch it early. Correct usage of latex condoms greatly reduces, but does not completely eliminate, the risk of catching or spreading syphilis.
NIH: National Institute of Allergy and Infectious Diseases