Soft Edges and a Swollen Groin

A 28-year-old previously healthy man presents to an STI clinic with 6 days of a progressively painful penile ulcer. He reports unprotected intercourse with a new partner approximately 10 days ago. He initially noticed a small erythematous papule on the prepuce that rapidly broke down into an open, painful sore over 2 to 3 days. He rates the pain as 8 out of 10, describing it as constant and worsened by touch. He denies fever, urethral discharge, prior similar lesions, or any known STI history.

Physical examination reveals an irregular ulcer approximately 1.5 cm in diameter on the prepuce with soft, non-indurated edges, undermined borders, and a grayish-yellow purulent base that bleeds readily on contact. There are no vesicles, no satellite lesions, and no induration of the surrounding skin. On inguinal examination, there is a cluster of tender, matted lymph nodes in the left inguinal region with early fluctuance and overlying erythema.

A rapid plasma reagin (RPR) returns non-reactive. A swab of the ulcer base is sent for HSV PCR, which is pending. Urethral discharge is absent, and no gram-positive diplococci are identified on urethral smear. Point-of-care gonorrhea and chlamydia testing are negative. HIV testing is ordered but results are pending.