Which lesion is characteristic of primary syphilis?

• A. Painless chancre
• B. Painful ulcer with exudate
• C. Vesicular eruption on hands
• D. Condyloma lata

Answer: (A)

A painless, indurated chancre at the site of inoculation is the hallmark of primary syphilis. This lesion is a firm, clean-based ulcer with raised, indurated borders and is typically not tender. It usually appears about three weeks after exposure and can heal on its own within 3–6 weeks, even without treatment. The chancre is highly infectious because Treponema pallidum is present in the ulcer.

This set of features helps distinguish it from other ulcers: a painful ulcer with exudate suggests chancroid rather than syphilis; vesicular eruptions on the hands point to other vesicular diseases; condyloma lata are flat, moist, wart-like lesions seen in secondary syphilis, not in the primary stage.