Genital Warts Overview

Human papillomavirus (HPV) is a group of viruses that produce warts on the skin (cutaneous) and on the membranes that line body passages (mucosal) for which there is no cure. In many cases, HPV infection goes away on its own.

More than 70 types of HPV have been identified; types 6, 11, 16, 18, 31, and 35 are transmitted sexually and cause anogenital warts, also called genital warts.

Anogenital warts caused by types 6 and 11 typically appear externally, on the penis, vulva, or anus. Types 16 and 18 cause warts on the mucous membranes (epithelium) that line the vagina, cervix, rectum, or urethra and are associated with cervical cancer and rectal or anal cancer. Infection is serious, although most cases do not lead to cancer.

Anogenital warts may be located deep in the epithelium of the vagina, urethra, or rectum and may be confined to an early isolated outbreak, depending on their type. For these reasons, up to 50% of infected people are unaware that they have genital warts. Untreated genital warts can eventually grow, spread, and form large clusters.

Incidence and Prevalence of Genital Warts

According to the Centers for Disease Control and Prevention (CDC), an estimated 20 million people in the United States are infected with HPV and about 5.5 million are exposed to the virus each year. Approximately 1 percent of sexually active adults in the United States have genital warts. The CDC reports that new cases of genital warts appeared to decrease in 2012.

Infection is most common in people aged 15 to 40 and affects men and women equally. As many as 50-75% of sexually active people are infected with HPV during their lifetime, and in most cases, the infection causes no symptoms and resolves without treatment.

Approximately 90% of men infected with HIV also have HPV. Persistent HPV infection in women is the primary risk factor for cervical cancer.

Causes and Risk Factors for Genital Warts

The human papillomavirus is transmitted through vaginal, oral, and anal sex. Many researchers believe that cultural norms for sexual behavior (more people having sex at a younger age and with multiple sex partners) have led to the increase in HPV infection. Because symptoms can be slow to appear and are usually painless, infected people can spread HPV unknowingly.

Those with a suppressed immune system are at higher risk for contracting infection that produces warts.

Signs and Symptoms of Genital Warts

Anogenital warts usually appear 3 or 4 months after exposure, typically on the vulva, cervix, penis, scrotum, anus, or inside the vagina or rectum. Oral sex may lead to warts in the mouth and throat. Warts may be red, pink, whitish, or gray. They are usually soft, flat, and irregularly shaped and are usually painless unless irritated by contact. Itching and burning are common once warts become irritated. Discomfort may increase as the warts enlarge, become raised, multiply into cauliflower-shaped clusters, or ulcerate. Ulcerated warts may bleed, itch, and produce a discharge with an unpleasant odor. Warts that develop inside the vagina may cause painful intercourse.

Various health complications may develop, depending on where the warts are located. Symptoms range from localized discomfort and pain to bleeding and difficulty in urination, defecation (if they form in the urethra, penis, vagina, anus, or rectum), or swallowing (if they form in the mouth or throat). Infected pregnant women can pass infection to their infants.

High-risk HPV can take 5 to 30 years to progress to cancer.

Genital Warts Diagnosis

External warts are usually diagnosed visually. A procedure called colposcopy involves treating otherwise hard-to-see warts with vinegar (acetic acid), which causes them to whiten and stand out. This is particularly useful in women. A biopsy, in which a sample of the wart is removed for analysis, may be performed to detect cancer. Vaginal and anal Pap smears are commonly performed to check for cancerous cells in both men (anal) and women.

Treatment for Genital Warts

There is no cure for HPV. In many cases, infection goes away on its own. Management involves removing warts and monitoring for the development of cancer cells. Removal may involve freezing with liquid nitrogen (cryotherapy), burning (electrocautery), laser removal, or surgical removal (excision). Cryotherapy is typically used to remove cervical warts, while larger external warts are often surgically removed. Side effects include local irritation, ulceration, and, sometimes, scarring.

Interferon-∂, (alpha interferon, a drug derived from a chemical made in the body) is injected directly into warts (sometimes after the wart is burned with electrocauterization) to eliminate or significantly reduce them. Injections are usually given 3 times a week for a few weeks.

Creams and chemical gel treatments, such as podophyllin and trichloracetic acid (TCA), are applied weekly to external warts by a physician to destroy tissue. Self-applied, prescription treatments such as imiquimod (Aladra®) and podofilox (Condylox®) are typically used 2 or 3 times weekly for several weeks, but no more than 3 or 4 months. Local skin irritation is a common side effect. These treatments are not approved for internal warts.

Regardless of the treatment method, recurrence is common because the virus lies dormant in skin cells after the warts are removed. Removing warts may reduce the risk for HPV transmission, but there is no evidence for this.

Genital Warts Prevention

Routine Pap smears are recommended for women and for men who have sex with men (anal Pap smear) to ensure early detection and effective treatment. Barrier contraception (e.g., condom, diaphragm) is recommended to help prevent disease transmission.

In June of 2006, the Food and Drug Administration (FDA) approved a cervical cancer vaccine for girls and women between the ages of 9 and 26. This vaccine (Gardasil®) has been shown to protect against the human papillomavirus (HPV).

In October 2009, the FDA approved Gardasil for use in boys and men between the ages of 9 and 26 to prevent genital warts caused by HPV types 6 and 11. Three injections of the vaccine are administered over a 6-month period. Side effects include headache, fever, and injection site reactions (e.g., pain, itching, redness, swelling, bruising).

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 10 Jun 1998

Last Modified: 13 Mar 2014