Primary syphilis
The first sign of syphilis is typically a painless sore called a chancre, appearing 10–90 days after exposure (average 21 days). It usually appears at the site of infection — on the genitals, anus, or mouth. Because the sore is painless and often hidden, it is frequently missed. It heals on its own within 3–6 weeks even without treatment, but the infection remains.
Secondary syphilis
Weeks to months after the chancre heals, secondary syphilis develops. The most recognisable sign is a non-itchy rash that often covers the palms of the hands and soles of the feet — a combination that is highly characteristic. Other symptoms include flu-like illness, swollen lymph nodes, and patchy hair loss. These symptoms also resolve on their own, but the infection progresses.
Latent syphilis
After the secondary stage, syphilis enters a latent phase with no symptoms. Early latent syphilis (less than 2 years) carries a higher transmission risk. Late latent syphilis can persist for years or even decades. The infection can still be passed to sexual partners and — in pregnant women — to the baby (congenital syphilis).
Tertiary syphilis
Without treatment, a proportion of people develop tertiary syphilis years later. This can cause serious damage to the cardiovascular system (aortitis, aneurysm), the central nervous system (neurosyphilis), and the formation of soft tissue masses called gummas. Neurosyphilis can cause dementia, vision problems, and paralysis. These complications are now rare due to antibiotic availability.
Testing and treatment
Syphilis is diagnosed by a blood test. Most tests can detect infection 6 weeks after exposure; a definitive result is typically available at 3 months. Treatment with penicillin (usually a single intramuscular injection for early stages) is highly effective. Partner notification is essential. Follow-up blood tests are recommended to confirm the infection has been cured.