Genital Ulcer — SCE Dermatology MCQ

Instant feedback + full explanation. One question, done properly.

ModerateGenital DermatologyGenital UlcerSCE Dermatology

A 35-year-old woman presents with a painful solitary ulcer on her vulva that has been present for 3 weeks. She is sexually active. RPR/VDRL is negative. HSV PCR is negative. She is afebrile. Biopsy shows non-specific chronic inflammation. What is the most important next step?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: C — Repeat syphilis serology in 2-4 weeks (as serology may be negative in early primary syphilis) and consider other STI testing

The correct answer is C, repeat syphilis serology in 2-4 weeks (as serology may be negative in early primary syphilis) and consider other STI testing. A solitary painful genital ulcer in a sexually active adult is a classic presentation of a primary chancre, but RPR/VDRL can be falsely negative in the window period before seroconversion, and non-specific chronic inflammation on biopsy does not exclude syphilis since spirochaetes are often not identified on routine histology. Current BASHH guidance advises repeat serological screening after an initial negative test in patients with PCR or dark ground negative ulcerative lesions that could be syphilitic, reflecting the limited sensitivity of a single early test. As HSV PCR is also negative, a broader STI screen (chancroid, lymphogranuloma venereum, other treponemal causes) is needed before the diagnosis is excluded. Discharging now risks missing untreated primary syphilis, which carries onward transmission and complication risk.

Reference: https://www.nice.org.uk/guidance/conditions-and-diseases/skin-conditions