Chancre (Primary Syphilis)

Syphilis Sore

Overview

A chancre is the hallmark lesion of primary syphilis, caused by the spirochete Treponema pallidum. It presents as a painless, firm, round ulcer with a clean base and raised, indurated borders at the site of inoculation, typically appearing 10-90 days after sexual exposure. The chancre is highly infectious and will heal spontaneously in 3-6 weeks even without treatment, but the infection progresses to secondary syphilis if untreated.

Key Symptoms

  • Single, painless, firm, round or oval ulcer at the site of contact
  • Clean base with raised, indurated (hard) borders
  • Typically 1-2 cm in diameter
  • Non-tender, painless regional lymphadenopathy (swollen lymph nodes)
  • Most common on the genitals, anus, or lips/mouth
  • Heals spontaneously in 3-6 weeks without scarring, even without treatment

Affected Areas

Genitals, Anus and perianal area, Lips and oral cavity, Fingers (rare)

Care Instructions

  1. See a healthcare provider immediately for testing if a painless genital or oral ulcer develops.
  2. Diagnosis is confirmed with darkfield microscopy, RPR/VDRL, and treponemal antibody tests.
  3. Treatment is a single intramuscular injection of benzathine penicillin G 2.4 million units.
  4. All sexual partners should be notified, tested, and treated.
  5. Follow-up serologic testing is necessary to confirm treatment success.
  6. Screening for other sexually transmitted infections (HIV, gonorrhea, chlamydia) is recommended.

Medical Disclaimer: This information is for educational purposes only and does not replace professional medical advice. Always consult a qualified dermatologist for diagnosis and treatment.

Prevalence: Primary and secondary syphilis cases have been rising significantly; over 200,000 cases reported in the U.S. in 2022