Have unprotected sex (do not use condoms or do
not use them correctly). This risk is especially high among men who have sex with other men (MSM).
multiple sex partners, particularly if you live in an area of the country where
syphilis is more common.
Have a sex partner who has
Have sex with a partner who has multiple sex
Exchange sex for drugs or money.
Have human immunodeficiency virus (HIV) infection
and engage in any of the behaviors listed above.
Syphilis is contagious whenever an open sore or skin rash
is present. The risk of being infected with syphilis from a single sexual
encounter with an infected partner is approximately 3% to 10%.4
Infection with syphilis also increases a
person's risk of being infected with HIV. Syphilis causes open sores on the
genitals that allow the HIV infection to enter the body easily. Syphilis is
in general more common in people who are also infected with HIV.