Which Sexually Transmitted Infections Spread by Skin Contact?

Most sexually transmitted infections spread either by exposure to infected fluids or by direct contact with infected skin. A few, such as pubic lice, can be spread by even more casual contact. However, STI transmission via clothing or other objects is relatively rare.

Skin to skin contact STD transmission is possible for a number of different conditions. The STIs where skin to skin contact poses the biggest risk for transmission include: 

• Genital and oral herpes. Herpes is the STD people are often most concerned about being spread from skin to skin. Contact with these very contagious sores can pass herpes from person to person. In fact, most people with oral herpes are infected during childhood. Casual contact with relatives can lead to herpes transmission. Genital and oral herpes can also be transmitted via mouth to genital contact. Although HSV-2 somewhat prefers genital infection, HSV-1 can infect either location. 

• HPV. Both cancer-causing HPV varieties and the HPV varieties that cause genital warts are easily spread through skin contact. Fortunately, there are vaccines that help. The most common cancer and wart-causing varieties can be prevented by early vaccination against HPV. However, ideally, vaccination should occur before people become sexually active. That's why initial vaccination is recommended at age 11 or earlier, though it is possible to get it later.

• Syphilis. There is a growing concern about this disease spreading through contact with mouth sores during oral sex. Most people think of syphilis as an easily preventable disease. It is and it isn't. When sores are covered by a condom, condoms help. However, sores in the mouth and on other skin locations may go unrecognized and untreated. Those sores can still be contagious. That's why testing is still important for high-risk groups. 

• Molluscum contagiosum. This skin disease is more often thought of as a disease of childhood than an STD. However, molluscum contagiosum sores can be spread during sex as well. Although generally a painless infection, if the sores break open, they can become infected by other bacteria. Therefore, it's worth talking to a doctor about treatment. You can also cover sores to prevent skin-to-skin contact since treatment can be difficult. 

STIs that are transmitted by skin-to-skin contact may be difficult to fully prevent by safer sex. That's because barriers do not necessarily cover all potentially infectious skin.

In contrast, it is easier to effectively prevent transmission of STIs such as HIV and hepatitis that spread through bodily fluids by using condoms and other barriers. These STIs require exposure to infected secretions such as blood, semen, and vaginal fluids for transmission to take place. (Which secretions are infectious varies by disease.) Remember, though, HIV does not spread by casual contact or skin-to-skin contact.​