In most cases, your body's immune system defeats an HPV infection before it creates warts. When warts do appear, they vary in appearance depending on which kind of HPV is involved:

• Genital warts. These appear as flat lesions, small cauliflower-like bumps or tiny stemlike protrusions. In women, genital warts appear mostly on the vulva but can also occur near the anus, on the cervix or in the vagina.

In men, genital warts appear on the penis and scrotum or around the anus. Genital warts rarely cause discomfort or pain, though they may itch or feel tender.

• Common warts. Common warts appear as rough, raised bumps and usually occur on the hands and fingers. In most cases, common warts are simply unsightly, but they can also be painful or susceptible to injury or bleeding.
• Plantar warts. Plantar warts are hard, grainy growths that usually appear on the heels or balls of your feet. These warts might cause discomfort.
• Flat warts. Flat warts are flat-topped, slightly raised lesions. They can appear anywhere, but children usually get them on the face and men tend to get them in the beard area. Women tend to get them on the legs.

Cervical cancer

Nearly all cervical cancers are caused by HPV infections, but cervical cancer may take 20 years or longer to develop after an HPV infection. The HPV infection and early cervical cancer typically don't cause noticeable symptoms. Getting vaccinated against HPV infection is your best protection from cervical cancer.

Because early cervical cancer doesn't cause symptoms, it's vital that women have regular screening tests to detect any precancerous changes in the cervix that might lead to cancer. Current guidelines recommend that women ages 21 to 29 have a Pap test every three years.

Women ages 30 to 65 are advised to continue having a Pap test every three years, or every five years if they also get the HPV DNA test at the same time. Women over 65 can stop testing if they've had three normal Pap tests in a row, or two HPV DNA and Pap tests with no abnormal results.

HPV infection occurs when the virus enters your body, usually through a cut, abrasion or small tear in your skin. The virus is transferred primarily by skin-to-skin contact.

Genital HPV infections are contracted through sexual intercourse, anal sex and other skin-to-skin contact in the genital region. Some HPV infections that result in oral or upper respiratory lesions are contracted through oral sex.

If you're pregnant and have an HPV infection with genital warts, it's possible your baby may get the infection. Rarely, the infection may cause a noncancerous growth in the baby's voice box (larynx).

Warts are contagious. They can spread through direct contact with a wart. Warts can also spread when someone touches something that already touched a wart.

HPV infections are common. Risk factors for HPV infection include:

• Number of sexual partners. The more sexual partners you have, the more likely you are to contract a genital HPV infection. Having sex with a partner who has had multiple sex partners also increases your risk.
• Age. Common warts occur mostly in children. Genital warts occur most often in adolescents and young adults.
• Weakened immune systems. People who have weakened immune systems are at greater risk of HPV infections. Immune systems can be weakened by HIV/AIDS or by immune system-suppressing drugs used after organ transplants.
• Damaged skin. Areas of skin that have been punctured or opened are more prone to develop common warts.
• Personal contact. Touching someone's warts or not wearing protection before contacting surfaces that have been exposed to HPV — such as public showers or swimming pools — might increase your risk of HPV infection.

• Oral and upper respiratory lesions. Some HPV infections cause lesions on your tongue, tonsils, soft palate, or within your larynx and nose.
• Cancer. Certain strains of HPV can cause cervical cancer. These strains might also contribute to cancers of the genitals, anus, mouth and upper respiratory tract.