A50-A64: Infections with a predominantly sexual mode of transmission

A51: Early syphilis

Early syphilis is the initial stage of syphilis infection, a sexually transmitted disease caused by the bacterium Treponema pallidum. It is typically spread through direct contact with a syphilis sore or rash during sexual activities. Initial symptoms often include a single sore (called a chancre), but there may be multiple sores. The sore is the location where syphilis entered your body. It is usually round, firm, painless and can appear at the site of sexual contact - typically, the genitals, rectum or mouth. If not treated immediately, syphilis can progress to later stages leading to long term complications, including damage to the brain, nerves, eyes, heart, blood vessels, liver, bones, and joints. Early detection and treatment can prevent these serious health problems from developing.