Painless indurated genital ulcer on the genitals is most consistent with which diagnosis?

• A. Chancroid
• B. Syphilis
• C. LGV
• D. Genital herpes

Answer: (B)

A painless, indurated genital ulcer is the classic presentation of primary syphilis. The chancre caused by Treponema pallidum is typically a single, firm, clean-based ulcer that is not painful, often with mild regional lymphadenopathy. This painless induration helps distinguish it from other causes: chancroid usually produces a painful, ragged, purulent ulcer with tender lymph nodes; genital herpes causes painful, multiple vesicular or ulcerative lesions; LGV may start with a small, often unnoticed lesion followed by painful inguinal lymphadenopathy rather than a prominent indurated ulcer. So the painless, firm chancre best fits primary syphilis. Serologic testing and appropriate antibiotic treatment are indicated.