What is syphilis? Syphilis is a sexually-transmitted infection (STI) caused by bacteria. If you have it, it can affect your entire body. If left untreated, syphilis can cause serious complications.

How do I get it? Syphilis can spread through unprotected vaginal, anal, and oral sex. It can be passed on whether the infected person has symptoms or not, but there is a higher chance of transmission if you come into contact with a sore. It can also be spread through kissing if there is a sore in your mouth.

What are the signs and symptoms? There are three stages to the infection. In its first stage (a week to three months after exposure) syphilis causes sores to appear around the vagina, penis, and anus, and inside the mouth. The sores may not be painful and may come and go on their own. Some people who have syphilis don’t get sores, or they don’t see them because they’re inside the vagina, anus, mouth, or throat.

These symptoms will then go away, and then a couple of months later, the person will experience “flu”-like symptoms, including fever and swollen lymph nodes. There may also be a rash, which can look like many other skin conditions. This is the second stage.

Some people never have further symptoms. People who get further symptoms may have to wait years, even decades, for them to show up. This is known as late-stage syphilis. By now the bacteria have caused significant damage throughout the body. These may include blindness, deafness, skin ulcers, heart disease, liver damage, paralysis, and dementia. For many people, this stage ends in death. People who have syphilis combined with HIV infection can move much more rapidly to this serious stage if left untreated.