GUD Cannot Distinguish Clinically — SCE Infectious Diseases MCQ

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HardSTIsGUD Cannot Distinguish ClinicallySCE Infectious Diseases

A patient has a new genital ulcer and syphilis, herpes simplex and chancroid are all possible. Which diagnostic principle is correct?

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Correct answer: B — Clinical appearance alone is unreliable, so obtain pathogen-specific laboratory testing

The best answer is “Clinical appearance alone is unreliable, so obtain pathogen-specific laboratory testing”. Ulcer pain, edge and lymphadenopathy overlap; lesion HSV NAAT, syphilis serology with repeat testing when early, and targeted tests based on travel and epidemiology are required. Genital-ulcer morphology overlaps substantially; syphilis serology and lesion NAAT for herpes or other pathogens are required rather than relying on pain or edge characteristics alone. A sustained fourfold rise in non-treponemal titre after prior treatment supports reinfection or treatment failure and requires clinical reassessment and retreatment.

Reference: BASHH genital-ulcer guidance: https://www.bashh.org/resources/6/genital_ulceration_2024/ BASHH syphilis guideline: https://www.bashh.org/resources/25/syphilis_2024/