[unseennude]

A 52-year-old man with no clinically significant medical history presents to the emergency department with a chief complaint of a "rash on my penis." The patient states that the rash first appeared 1 week ago. He denies any pruritus or groin pain in the area of the lesion and denies dysuria and urethral discharge. This is the first time he has had such a rash. He admits to having several recent sexual partners.

On physical examination, his vital signs are normal. The patient has a well-demarcated, ulcerated lesion on ventral aspect of his penis (see Image below). The lesion is not tender to palpation. No other lesions are noted, and no discharge is observed from the urethra. Findings on testicular examination are unremarkable with the exception of bilateral prominent inguinal lymphadenopathy. The remaining physical findings, including cardiac and abdominal findings, are unremarkable.





What is the diagnosis, and what empiric treatment is necessary?
Hint: The lesion is characteristically painless.