A bacterial infection usually spread by sexual contact that starts as a painless sore.
Syphilis is a bacterial infection usually spread by sexual contact. The disease starts as a painless sore, usually on the genitals, rectum, or mouth. It's spread by contact with these sores.
Syphilis develops in stages, and symptoms vary with each stage. After the initial sore heals, a rash may appear.
Syphilis is treated with penicillin.