Common symptoms
Painless sore (chancre)
A firm, round, painless sore at the site of infection (Primary stage)
Skin rash
Non-itchy rash on the palms and soles of the feet (Secondary stage)
Fever and fatigue
Flu-like symptoms including fever, sore throat, and swollen lymph nodes
Latent phase
No symptoms despite the infection remaining in the body
Organ damage (late stage)
Damage to the heart, brain, nerves, and other organs if untreated
Syphilis is a bacterial infection caused by Treponema pallidum that progresses through distinct stages if left untreated. The primary stage features a painless sore; the secondary stage causes a rash and flu-like symptoms; the latent stage has no symptoms; and tertiary syphilis can cause severe organ damage.
Each stage of syphilis can be treated with penicillin-based antibiotics. Earlier stages respond more rapidly to treatment. Tertiary syphilis may cause irreversible damage even with treatment.
After treatment, follow-up blood tests are needed at 6 and 12 months to confirm the infection has been cleared. All recent sexual partners must be notified, tested, and treated.