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Chancroid — SCE Infectious Diseases MCQ

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ModerateSTIsChancroidSCE Infectious Diseases

A 35-year-old woman presents with a 2-week history of genital ulceration and bilateral inguinal lymphadenopathy. She reports recent travel to sub-Saharan Africa. Clinical examination shows three shallow, painful ulcers with ragged edges. HSV PCR is negative, RPR non-reactive, TPHA non-reactive. A Gram stain of ulcer material shows 'railroad track' parallel chains of Gram-negative coccobacilli. What is the most likely diagnosis?

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Correct answer: B — Chancroid (Haemophilus ducreyi)

Multiple painful genital ulcers with ragged undermined edges and tender inguinal lymphadenopathy, combined with Gram-negative coccobacilli in parallel chains ('railroad tracks' or 'school of fish'), after travel to Africa is classic for chancroid (H. ducreyi). HSV and syphilis have been excluded by testing. LGV causes painless ulcers with unilateral lymphadenopathy. Granuloma inguinale (Donovanosis) causes painless beefy red ulcers without lymphadenopathy. Treatment is Azithromycin 1 g single dose or Ceftriaxone 250 mg IM.

Reference: BASHH 2019 – Genital ulcer guidelines; WHO 2024 – STI management