Snapshot A 35-year-old man presents to the clinic after noticing an ulcer on his penis. He is unsure how long the ulcer has been present, as he has not felt pain in the area. He denies any symptoms of discharge, rash, or dysuria. Sexual history is notable for unprotected sexual intercourse with multiple partners over the past year. On physical examination, there is a 1-cm ulcer on the underside of the penis and bilateral inguinal lymphadenopathy. Dark-field microscopy reveals motile, spiral-shaped organisms. Introduction Classification login to view 2 more bullets Epidemiology login to view 10 more bullets Pathogenesis login to view 6 more bullets Associated conditions login to view 3 more bullets Prognosis login to view 4 more bullets Presentation Primary syphilis login to view 3 more bullets Secondary syphilis login to view 6 more bullets Tertiary syphilis login to view 13 more bullets Congenital syphilis login to view 9 more bullets Studies Labs login to view 6 more bullets Microscopy login to view 2 more bullets Treponema Pallidum Labs VDRL FTA Interpretation + + Active infection + - Probably false positive - + Successfully treated Differential Herpes simplex virus login to view 1 more bullet Haemophilus ducreyi login to view 1 more bullet Lymphogranuloma venereum login to view 1 more bullet Klebsiella granulomatis login to view 1 more bullet Treatment Medical login to view 5 more bullets Complications Jarisch-Herxheimer reaction login to view 2 more bullets complications of tertiary syphilis login to view 3 more bullets