A 30-year-old man presents with a small painless genital papule that healed unnoticed, followed by painful unilateral inguinal lymphadenopathy. Multiple matted nodes are separated by a horizontal furrow above and below Poupart ligament. Aspiration of a bubo yields sterile pus. What is the most likely causative agent?

• A Chlamydia trachomatis serovars L1, L2 and L3 ✓
• B Klebsiella granulomatis
• C Haemophilus ducreyi
• D Treponema pallidum

Explanation

The groove sign created by the inguinal ligament separating femoral from inguinal nodes is characteristic of lymphogranuloma venereum caused by A trachomatis biovar L1 to L3. The primary lesion is a transient painless herpetiform papule or ulcer. Chancroid produces a painful non-indurated ulcer with tender suppurative bubo but no groove sign, which eliminates option C. Donovanosis gives beefy red hypertrophic ulcers without bubo formation.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.