Syphilis is a sexually transmitted infection (STI). There are four stages of the disease: primary, secondary, latent, and tertiary (also known as neurosyphilis). Primary Stage. During the first (primary) stage of syphilis, you may notice a single sore or multiple sores. The sore is the location where syphilis entered your body. Sores are usually (but not always) firm, round, and painless. The sore usually lasts 3 to 6 weeks and heals regardless of whether or not you receive treatment. Even after the sore goes away, you must still receive treatment. This will stop your infection from moving to the secondary stage. Secondary Stage. During the secondary stage, you may have skin rashes and/or mucous membrane lesions. Mucous membrane lesions are sores in your mouth, vagina, or anus. This stage usually starts with a rash on one or more areas of your body. Latent Stage. The latent stage of syphilis is a period of time when there are no visible signs or symptoms of syphilis. If you do not receive treatment, you can continue to have syphilis in your body for years without any signs or symptoms. Tertiary Stage. Most people with untreated syphilis do not develop tertiary syphilis. However, when it does happen it can affect many different organ systems. These include the heart and blood vessels, and the brain and nervous system. Tertiary syphilis is very serious and would occur 10–30 years after your infection began. In tertiary syphilis, the disease damages your internal organs and can result in death.