Diagnosis and Treatment
Diagnosis is made by symptoms, blood tests (required by many states before issuing marriage licenses), and microscopic identification of the bacterium. Until the advent of penicillin in the 1940s, treatment for syphilis was with mercury, arsenic, and bismuth. Penicillin is the antibiotic of choice for all stages of syphilis treatment, but penicillin-resistant organisms have complicated treatment of the disease. Even late-stage syphilis can be cured, but damage that has already occurred cannot be reversed. Despite available treatment, the incidence of syphilis in the United States was on the rise until 1990, when it began declining significantly; since 2000, it has risen again.
See also Ehrlich, Paul.