What is syphilis?
Syphilis is caused by the bacterium Treponema pallidum. It progresses through stages, each with a different presentation, and it is curable with antibiotics at every stage — though damage already done cannot always be reversed.
Diagnik Health Library · Updated
The stages
- Primary: a single painless sore (chancre) at the site of infection, easily missed.
- Secondary: a rash — often on the palms and soles — plus fever, sore throat or swollen lymph nodes.
- Latent: no symptoms at all, sometimes for years, while the infection persists.
- Late (tertiary): serious damage to the heart, brain and other organs in a minority of untreated cases.
Why it matters now
Reported syphilis cases in the United States have increased substantially over the last decade, including congenital syphilis passed during pregnancy. Because early syphilis is often painless and short-lived, many infections are only found through testing.
Treatment
Syphilis is treated with antibiotics prescribed by a clinician. The stage determines the regimen, which is exactly why a reactive screening result needs clinical follow-up rather than self-management.
Tests mentioned in this guide
Frequently asked questions
- Is syphilis curable?
- Yes. Antibiotics cure the infection at any stage, although organ damage from late-stage disease may be permanent.
- Can syphilis have no symptoms?
- Yes. The latent stage produces no symptoms, and the primary sore is painless and often unnoticed.
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Syphilis symptoms
The painless sore, the rash people mistake for an allergy, and the silent phase.
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Syphilis testing
Screening finds antibodies; a clinician works out whether treatment is needed now.
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How syphilis is transmitted
Direct contact with a sore is the route — including during oral sex.
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Sources
Educational information only, not a medical diagnosis or treatment advice. Screening results always need confirmation by a clinician.
This guide is general health information about screening tests. It is not a diagnosis and does not replace care from a clinician. See our medical disclaimer.