Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum. It has stages, and skin signs are common early on. It’s curable with antibiotics, but early diagnosis matters.
How it spreads
- Sexual contact (oral, vaginal, anal) and through pregnancy to the baby.
- It’s more common among people with multiple partners and can occur alongside other STIs, including HIV.
Stages and skin signs
- Primary syphilis (about 3 weeks after exposure)
- A single, firm, painless sore (chancre) at the site of infection (genitals, mouth, anus).
- The sore has a clean base and firm edges; nearby lymph nodes may swell.
- It heals in 3–6 weeks even without treatment—but the infection continues.
- Secondary syphilis (weeks to months later)
- Rash that may be faint or obvious, often on the trunk and can involve palms and soles.
- Spots can be pink, coppery, or wart-like moist bumps in folds (condyloma lata).
- Fever, sore throat, swollen glands, patchy hair loss, mouth sores can occur.
- Symptoms can come and go.
- Latent stage
- No symptoms, but blood tests are positive. Without treatment, infection persists and may progress.
- Tertiary/late syphilis (years later, uncommon with modern care)
- Can affect heart, brain, nerves, and other organs. Preventable with early treatment.
Congenital syphilis
- Passed from pregnant person to baby; can cause miscarriage, stillbirth, or serious illness in the newborn. Routine screening in pregnancy is essential.
Diagnosis
- Blood tests (non-treponemal and treponemal). Lesion swabs can help in certain cases.
- Testing for other STIs, including HIV, is often recommended.
Treatment
- Penicillin G injection is the standard. Alternatives exist for some, but penicillin is preferred, especially in pregnancy.
- Follow-up blood tests make sure treatment worked.
- Avoid sex until your clinician confirms you’re no longer contagious; notify partners so they can get tested/treated.
When to seek care
- Any painless genital/mouth sore, unexplained rash (especially involving palms/soles), or new wart-like lesions in body folds.
- If you are pregnant and think you were exposed.
Prevention
- Condoms reduce risk but don’t fully protect against sores on uncovered skin.
- Regular STI screening if sexually active with new or multiple partners.
- Prompt evaluation of any suspicious sores or rashes.