Types of HPV

There are more than 200 types of HPV (human papillomavirus). All types of HPV can live only in certain cells called squamous epithelial cells. These are normal cells found on the surface of the skin (cutaneous) and on moist surfaces and membranes (called mucosal membranes or mucosal surfaces).

The different types of HPV are identified by numbers and are grouped based on whether they infect cutaneous (skin) cells or mucosal (genital) cells.

This diagram shows the different groups of HPV types and the problems each group can cause.

Cutaneous (skin) HPV types

Many HPVs are cutaneous types, meaning they invade and live in cells on the skin. Cutaneous HPVs can cause warts on top of the skin in areas such as hands, feet, arms, and legs. These are common warts that are only on the skin. They are not the same as genital warts.

Mucosal (genital) HPV types

Mucous or mucosal membranes are moist surface layers that line organs and parts of the body that open to the outside, such as the:

• Vagina, anus, cervix, and vulva (area around the outside of the vagina)
• Inner foreskin and urethra of the penis
• Inner nose, mouth, and throat
• Trachea (windpipe) and bronchi (smaller breathing tubes branching off the trachea)
• Inner eyelids

Mucosal HPV types invade and live in cells on mucosal surfaces. They are also called genital (or anogenital) HPV types because they often affect the anal and genital areas that have mucosal surfaces. But these types can also infect the lining of the mouth and throat that also have mucosal membranes.

Mucosal or genital HPV types are further broken down into low-risk and high-risk types, depending on their ability to cause cancer.

Low-risk mucosal types

HPV 6 and HPV 11 are low-risk HPV types. They tend to cause genital warts and rarely cause cancer. Some of these types may have proteins in them, such as E6 and E7 that might add to their ability to cause cancer. Having a low-risk genital HPV infection can cause cauliflower-shaped warts on or around the genitals or anus. Warts may appear in areas that aren’t always noticed, such as the cervix and vagina.

High-risk mucosal types

HPV 16, HPV 18, HPV 31, HPV 33, and HPV 42 are examples of high-risk HPV types that can cause cancer. These HPV types can sometimes avoid the body's immune system, so the body can't get rid of the HPV. The infection can linger over time, causing damage to normal cells that can turn them into abnormal cells, which might later become cancer. In fact, high-risk HPV types are known to cause 6 different types of cancer. Learn more in Cancers Linked with HPV.