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Primary syphilis — ABFM Board MCQ

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EasyInfectious diseasePrimary syphilisABFM Board

A 33-year-old man has a painless penile ulcer and nontender inguinal lymphadenopathy. Dark-field microscopy is unavailable and RPR is reactive. Which of the following is the most likely diagnosis?

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Correct answer: B — Primary syphilis

A painless chancre with reactive serology is typical of primary syphilis.

Reference: CDC STI Treatment Guidelines: https://www.cdc.gov/std/treatment-guidelines/default.htm