A 32 year old man presents with a painless oral ulcer for one week. Further questioning reveals that he had unprotected orogenital sex with two separate partners during the preceding month. He is otherwise well, with an unremarkable medical history.
You remember that dark field microscopy of oral lesions is not recommended.
The Rapid Plasma Reagin test is strongly reactive.
The Treponema pallidum Particle Agglutination assay is reactive.
A biopsy will be arranged next week.