Understanding syphilis

Syphilis is passed on through close contact with an infected sore, usually during vaginal, anal or oral sex. It can also pass from a pregnant person to their baby.

The NHS describes a small, usually painless sore in the early stage, which can be missed. Later, a rash, flu-like symptoms or patchy hair loss may appear. Without treatment the infection can stay hidden for years and may later cause serious problems.

Syphilis is usually diagnosed with a blood test. Rapid finger-prick screening tests detect antibodies, which can remain after past, treated infection, so a positive result always needs clinical confirmation. Treatment is with antibiotics prescribed by a clinician.

• Syphilis screening kit

• NHS – Syphilis (nhs.uk/conditions/syphilis)

Last reviewed 5 November 2026. This guide has not been clinically reviewed by a named professional.