Reexamining Syphilis: An Update on Epidemiology, Clinical Manifestations, and Management

Molly E Kent, PharmD; Frank Romanelli, PharmD MPH BCPS


The Annals of Pharmacotherapy. 2008;42(2):226-236. 

In This Article


Reporting of syphilis cases in the US began in 1941; since that time, the incidence of syphilis has varied greatly.[3,8] Following the introduction of penicillin, the incidence of primary and secondary syphilis fell from 66.4 cases per 100,000 persons in 1947 to 3.9 cases per 100,000 persons in 1956. The incidence of primary and secondary syphilis continues to cycle with peaks and troughs and reached an all-time low in 2000, with 2.1 cases per 100,000 persons.[9] In 1999, the Centers for Disease Control and Prevention (CDC) launched the National Plan to Eliminate Syphilis from the US. Following the 2000 nadir, however, syphilis rates again began to rise, reaching 2.7 cases per 100,000 persons in 2004.[3] This increase in primary and secondary syphilis is thought to be due primarily to an increased incidence among men. Today, more than 60% of new cases of syphilis occur in men who have sex with men (MSM), and these cases are often associated with HIV coinfection and high-risk sexual behavior.[3] HIV coinfection rates have been reported to be as high as 60% in Los Angeles, 51% in Chicago, 60% in San Francisco, and 34% in Houston.[10] While rates of primary and secondary syphilis in the US have increased among men in recent years, they have remained stable among women.[3,9] Additionally, rates of primary and secondary syphilis among women and rates of congenital syphilis have shown an average yearly decrease of 19.8% and 17%, respectively, from 1991 to 2004. The racial disparity among African Americans and non-Hispanic whites peaked in 1992 with a ratio of 62:1 and has been declining ever since with a ratio of 5.6:1 in 2004.

Similar trends in syphilis rates have been documented in other parts of the world. In England, following a trough between 1995 and 1998, the number of cases of syphilis increased dramatically due to a small number of isolated outbreaks.[4] From 1998 to 2000, the number of cases of infectious syphilis diagnosed in women increased by 53% (from 102 to 156) and more than doubled in men (from 172 to 372). This increase continued from 2000 to 2001, when the overall diagnosis of syphilis increased by 119%.[5] The majority of these cases were in males and over half occurred in MSM. Within this same time period, outbreaks of syphilis were also reported in several Western European nations, with 70-95% of cases being diagnosed among MSM.[11]

Russia and the now independent states of the former Union of Soviet Socialist Republics have also experienced a recent increase in syphilis cases. After achieving a notification rate of 4.2 cases per 100,000 in 1988, the rate rose to 263 per 100,000 in 1996.[6,7] Many social changes have been hypothesized to be contributing to this recent increase including opening of borders, a rapid growth in prostitution, glamorization of sexuality from the Western world, and a partial loss of free diagnosis and mandatory treatment from the Soviet Ministry of Health.[12]


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