Syphilis is a sexually transmitted disease (STD), caused by infection with a bacterium. This bacterium will initially cause an infection in the penis, vagina, anus or even in the mouth. If the disease is left untreated, other organs can eventually become infected and get damaged.


The bacterium Treponema pallidum is the causer of syphilis. The bacterium inhabits in the mucosa of the penis, vagina, anus or mouth, and causes an infection there. During unsafe sex, an infected person can transfer the bacterium to another person, as the mucosa comes into contact with each other. Syphilis can also be transferred by kissing, but only if there is a syphilis sore at the lips or in the mouth. From the mucosa, the bacteria ultimately get into the bloodstream and spread to other organs. During pregnancy, the infection can be transferred onto the baby. After infection, it takes ten to ninety days (with an average of three weeks) before the first symptoms occur.


At the site of infection, one or more sores arise. This can be on or in the penis, vagina, anus or mouth. The sore can be about one centimeter in size, feels hard and usually doesn’t hurt. The sore is sometimes difficult to see, because it can be located in the vagina or anus. The lymph nodes near the sore are swollen. Even without treatment, it disappears on its own within two to three weeks. However, the disease is not gone. Several weeks or months later, the second stage of the disease begins. The bacterium has spread then via the bloodstream throughout the entire body. A patient can have the following signs and symptoms:

Later, often after many years, various organs can be damaged, such as the heart and the aorta (vascular changes), brains (mental deterioration), spinal cord (so paralysis may occur) and bones (inflammation).


Three months after infection, syphilis can be demonstrated by a blood test. If there are symptoms, the infection can sometimes be detected earlier with a smear of the sore. At the first pregnancy check, blood is also tested for syphilis.


The treatment includes one or more penicillin injections. After the first injection(s), there may be a flu-like response, which is caused by the death of the syphilis bacteria. After the last injection, the patient has to come back several times for one to two years for blood tests and monitoring of possible symptoms. These follow-up checks are very important, especially in HIV-infected people. If the patient has had all the necessary injections, he or she cannot infect another person anymore. Only then, sexual contact is without risk again. During treatment, it’s better not to have sex. This prevents to keep infecting each other. If a patient wants to have sex anyway, use a condom.


Early treatment of syphilis ensures a good prognosis. If organ damage has occurred in later stages of the disease, it cannot be undone.