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Painless sore

Also called: Chancre, syphilis sore, painless ulcer

A painless sore on the genitals, anus, or mouth can be the first sign of syphilis, a sexually transmitted infection. The sore heals on its own, but the infection stays and can cause serious problems later. Syphilis is easy to test for and cure with antibiotics. Any new sore after sex should be checked.

Common causesSyphilis, other infections, injury
Usually serious?Can be
Get checked ifAny new sore, especially after sex
If you think it's an emergency, call 911.Thinking about suicide? Call or text 988.

Overview

A syphilis chancre is usually a firm, round, painless sore that appears 10 to 90 days after exposure and heals in 3 to 6 weeks. Without treatment, a rash on the palms and soles and flu-like symptoms may follow.

Syphilis can affect the brain, eyes, and heart if not treated, and can be passed to a baby during pregnancy. Herpes sores are usually painful.

When to get medical care

Call 911Not an emergency.
Get care todayVision changes, hearing loss, or severe headache with a recent sore or rash.
See a doctor soonAny new genital, anal, or mouth sore. A rash on the palms or soles. Possible syphilis exposure. Pregnancy.

Causes

Causes include syphilis, herpes, chancroid, LGV, injury, and, rarely, skin cancer.

OwieClear has pages on 3 conditions that can cause painless sore. Each shows how soon to get care.

Common causes

  • SyphilisSee a doctor if it doesn't get better

    A bacterial STI that often starts as a painless sore.

Less likely causes

What you can do at home

  • Avoid sex until tested and treated.
  • Tell partners so they can be tested.
  • Use condoms.

Medicines

Syphilis is cured with penicillin injections. Partners need treatment too.

At the doctor

A blood test finds syphilis.

Questions you may be asked

  • When the sore appeared
  • Sexual contacts
  • Rash or other symptoms
  • Pregnancy

The exam

An exam of the sore and skin.

Tests

  • Syphilis blood tests
  • Swab tests for herpes
  • HIV test

Prevention

Lower your risk.

  • Use condoms
  • Get tested regularly
  • Limit partners

Check your symptoms

Most symptoms have more than one possible cause. The symptom checker looks at all of your symptoms together, plus your age, and shows how soon to get care.

Start the symptom checker

Sources

Last updated 2026-11-13.