Syphilis is caused by the spirochete bacterium Treponema pallidum, a gram-negative bacterium that only infects humans. Syphilis is a sexually transmitted infection. Syphilis mainly infects men who have sex, accounting for up to 50 percent of cases of syphilis in the United States. Primary syphilis usually presents with a painless genital, rectal, or oropharyngeal lesion (more often multiple lesions that may be painful in patients with H.I.V.). Sites of sexual exposure. Following exposure, it takes around three weeks for a lesion/ papule to develop. The initial lesion will typically resolve with or without antibiotics within a few weeks. Regional lymphadenopathy may be present. Signs and symptoms of secondary syphilis are a rash, lymphadenopathy, and fever (sometimes mucosal lesions, headache, and or joint pain). Secondary syphilis begins weeks to months following primary syphilis. Latent syphilis does not have signs or symptoms but will demonstrate serologic evidence of syphilis infection. Infected persons may stay in latent syphilis for the rest of their lives and never develop tertiary syphilis. Tertiary syphilis can affect multiple sites (the central nervous system called neurosyphilis, possibly causing tabes dorsalis through infection of the dorsal columns of the spinal cord, or the eyes, ocular syphilis, the heart and aorta causing aortitis and possibly aortic aneurysm, among other organs). There are multiple tests to diagnose syphilis. The commonly known R.P.R. Rapid Plasma Reagin test is a nontreponemal test traditionally used as a screening test for syphilis. The V.D.R.L. test is also a nontreponemal screening test. These tests need to be confirmed with another more specific test, such as a Treponemal assay that tests for T. pallidum antibodies. There are multiple different T. pallidum immunologic tests. Some laboratories will perform a reverse sequence algorithm where the treponemal specific immunologic test is performed first followed reflexively if positive with a nontreponemal test. Treatment for primary, secondary, and early latent syphilis is a one-time intramuscular injection of 2.4 million units of penicillin G. This is the treatment for all early stages of syphilis (primary, secondary, and early latent). If there is a penicillin allergy in a pregnant person with a positive syphilis test, then penicillin desensitization is recommended because there is no alternative treatment for syphilis. A higher dosage of penicillin for a longer duration is needed to treat late latent and tertiary syphilis (weekly administration of intramuscular penicillin for three weeks). Neurosyphilis requires an even higher daily dosage of I.V. penicillin for around two weeks. Cerebrospinal fluid evaluation should be done if a patient with syphilis has neurologic signs or symptoms. There is a Grade A U.S.P.S.T.F. recommendation to screen non-pregnant high-risk adolescents and adults for syphilis. Additionally, screening for syphilis is recommended for all pregnant people with retesting for those at high-risk for syphilis at 28 weeks gestation to prevent congenital syphilis. There is no vaccine for syphilis. The U.S. Public Health Service was a part of the Tuskegee Study conducted in Alabama from 1932 to 1972, which followed black participants with syphilis and did not provide them with treatment for their condition even though penicillin became available and was known to effectively treat syphilis in the 1940s. In fact, the participants thought they were being treated for syphilis. However, they were actually given aspirin and iron supplements. The Belmont Report resulted from the Tuskegee Study, among other federal and legal actions. The three principles of the Belmont Report are respect of persons, beneficence, and justice.

References:

Recommendation: Syphilis Infection in Nonpregnant Adults and Adolescents: Screening | United States Preventive Services Taskforce (uspreventiveservicestaskforce.org)

STD Facts - Syphilis (cdc.gov)

CDC Syphilis Brochure

Bolan G. Sexually Transmitted Infections: Syphilis. In: Boulton ML, Wallace RB. eds. Maxcy-Rosenau-Last Public Health & Preventive Medicine, 16e. McGraw Hill; 2022. Accessed January 09, 2022.