Getting Syphilis From Oral Sex

Syphilis is easily spread by oral sex. Most people don't think of blow jobs and other oral sex activities as being things that put them at risk for syphilis. However, oral sex is actually a major reason why the number of syphilis infections is on the rise again after years of decline.

Syphilis is easily missed in the mouth. The early sores associated with primary syphilis are painless. The associated oral lesions of secondary syphilis can also be easily overlooked.

For that matter, even the classic secondary syphilis rash on the body, palms, and soles of the feet can be subtle. This, combined with a lack of screening of high risk individuals, definitely contributes to the spread of syphilis.

Syphilis can become a serious health concern. Therefore, it is worth taking preventative measures to protect yourself. Such measures may include using condoms or dental dams for oral sex, as well as practicing safe sex in general. Left undetected and untreated, syphilis can increase your risk of HIV and lead to systemic health problems. Also of concern for women is the possibility that a syphilis infection during pregnancy could lead to congenital syphilis, affecting a newborn. There has been a noticeable increase in congenital syphilis cases in recent years. The condition can be fatal for the child if not caught and treated promptly.

The Hypothesized Relationship Between Syphilis, Oral Sex, and HIV Prevention

Some people think that safe sex messaging around HIV prevention is one reason that oral syphilis is on the rise.

HIV is relatively unlikely to spread by oral sex. Therefore, many high-risk individuals consider oral sex to be safe sex. It is, unquestionably, relatively safe for HIV. (It's completely safe for pregnancy!) However, it's not at all safe for syphilis. Therefore, a move towards oral sex as a safe sex activity may have increased how common syphilis is in high-risk groups.

Is Syphilis Really On The Rise?

Data from the CDC is pretty clear. The number of cases of syphilis dropped precipitously through the 1990s. Then, starting in 2000, the number of cases began to go up again. However, these new syphilis cases were almost entirely seen in men - primarily men who have sex with men. The rate in men more than doubled between 2000 and 2014. The ratio of male to female cases also skyrocketed. It went from only slightly higher than 1:1 to more than 10:1 in the same period. Data suggests that many of these cases may have been spread through oral sex. However, that is difficult to prove conclusively. Oral sex is also certainly not the only factor involved.


Centers for Disease Control and Prevention. Sexually Transmitted Disease Surveillance 2014. Atlanta: U.S. Department of Health and Human Services; 2015.

Champenois K, Cousien A, Ndiaye B, Soukouna Y, Baclet V, Alcaraz I, Choisy P, Chaud P, Velter A, Gallay A, Yazdanpanah Y. Risk factors for syphilis infection in men who have sex with men: results of a case-control study in Lille, France. Sex Transm Infect. 2013 Mar;89(2):128-32. doi: 10.1136/sextrans-2012-050523.

Ciesielsk et al. (October 22, 2004) "Transmission of Primary and Secondary Syphilis by Oral Sex - Chicago, Illinois, 1998-2002." MMWR 53(41):966-968

Syphilis-CDC Fact Sheet.

Syphilis and Men Who Have Sex With Men-CDC Fact Sheet.