Syphilis is among the most fascinating of skin diseases. It may present to the dermatologist as a sexually acquired, contagious disease or as a congenitally acquired infection. When sexually acquired, it commonly coexists with at least one other sexually transmitted infection. Although syphilis is endemic worldwide, its steady decline over the last 400 years has been punctuated by epidemic peaks associated with unstable social conditions or upheavals. These changes include mass migrations and wars, as well as growing prosperity and economic reversals precipitating real or relative poverty. More recently, rates of primary and secondary syphilis have increased in the past decade, warranting renewed attention to the diagnosis and treatment of this disease.