27-year-old white man presents to his family doctor complaining of being tired all the time and having a slight fever for the past two weeks. He recently returned from a trip to Las Vegas, where he indulged in some of the infamous nightlife. His physical exam is unremarkable except for a macular rash over his trunk and on the palms of his hands. There are no lesions or ulcers on the penis. What organism is causing this man's illness?
High-Yield Explanation
Treponema pallidum Transmitted through unprotected sexual activity with an infected individual. Presents with the symptoms of secondary syphilis, which includes malaise, mild fever, and rash on the palms and trunk. The primary lesion (chancre) may go unnoticed because it is painless and subsides in a few weeks.