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Genital Warts (Human Papillomavirus Infection, or HPV Infection)
Genital warts (condylomata acuminata) are growths in or around the vagina, penis, or rectum caused by the human papillomavirus, which is sexually transmitted.
Different types of human papillomavirus (HPV) cause different infections, including visible genital warts and less visible warts in the cervix, vagina, anus, rectum, and throat (which increase the risk of certain cancers), as well as common skin warts.
Genital warts grow rapidly and sometimes cause burning pain.
Doctors identify visible warts based on their appearance, and they examine the cervix and anus to check for less visible warts.
Vaccines can prevent most types of HPV infection that can cause cancer.
Visible warts can usually be removed with a laser or by freezing (cryotherapy) or surgery, but sometimes drugs are applied to the warts.
In the United States, about 1.4 million people have genital warts, which are caused by HPV. About 79 million people have an HPV infection, and about 14 million are infected each year. About 80% of women have been infected at least once by age 50. Most infections go away within 1 to 2 years, but some persist. Persistent infection can increase the risk of certain types of cancer.
There are over 100 known types of HPV. Some types cause common skin warts (see Warts). Other types cause different types of genital infections:
External (easily seen) genital warts: These warts are caused by certain types of HPV, especially types 6 and 11. These types are transmitted sexually and infect the genital and rectal areas.
Internal (less visible) genital warts: Other HPV types, especially types 16 and 18, infect the genital area but do not cause easily visible warts. They cause tiny flat warts on the cervix or in the anus, which may be visible only with a magnifying instrument called a colposcope. These less visible spots usually cause no symptoms, but the HPV types that cause them increase the risk of developing cervical, vaginal, anal, and rectal cancer and therefore should be treated (see Cervical Cancer).
HPV can also be spread during oral sex, causing infections of the mouth and increasing the risk of throat cancer.
In men, warts usually occur on the penis, especially under the foreskin in uncircumcised men, or in the urethra. In women, genital warts occur on the vulva, vaginal wall, cervix, and skin around the vaginal area. Genital warts may develop in the area around the anus and in the rectum, especially in people who engage in anal sex. Warts cause no symptoms in many people but cause occasional burning pain, itching, or discomfort in some.
The warts usually appear 1 to 6 months after infection with HPV, beginning as tiny, soft, moist, pink or gray growths. They grow rapidly and become rough, irregular bumps, which sometimes grow out from the skin on narrow stalks. Their rough surfaces make them look like a small cauliflower. Warts often grow in clusters.
Warts may grow more rapidly and spread more widely in pregnant women and in people who have a weakened immune system, such as those who have human immunodeficiency virus (HIV) infection.
External genital warts usually can be diagnosed based on their appearance. If warts look unusual, bleed, become open sores (ulcerate), or persist after treatment, they should be removed surgically and examined under a microscope to check for cancer. Because syphilis can cause certain types of genital warts, doctors usually do a blood test for syphilis.
Colposcopy (see Diagnostic Procedures : Colposcopy) is done to check for less visible, internal warts on the cervix or in the anus. A stain may be applied to the area so that warts can be seen more easily. A sample taken from a wart may be analyzed using tests, such as the polymerase chain reaction (PCR). This test produces many copies of a gene, which may enable doctors to identify HPV’s unique genetic material (DNA). These tests help confirm the diagnosis and enable doctors to identify the type of HPV.
If women have warts on the cervix, a Papanicolaou (Pap) test is done to rule out other abnormalities (such as cervical cancer—see Cervical Cancer). If genital warts are diagnosed, women should have a Pap test and colposcopy of the vagina and cervix (using a magnifying instrument) twice a year so that any abnormalities can be identified and treated promptly.
There are two vaccines for HPV:
Both are given as injections into a muscle, usually in the upper arm. A new vaccine that protects against nine types of HPV is now available.
The quadrivalent vaccine protects against the two types of HPV (types 6 and 11) that cause more than 90% of genital warts. This vaccine also protects against the two types of HPV (types 16 and 18) that cause about 70% of cervical cancers. This vaccine can be used in girls and boys. It is recommended for girls and women aged 9 to 26 years old to prevent initial infection. Three doses are given, preferably at age 11 to 12 years. The vaccine should be given before girls and women become sexually active, but those who are sexually active should still be vaccinated. For boys, three doses of the vaccine are given, preferably at age 11 to 12 years. The vaccine is also given to boys aged 13 to 21 who have not had all three doses and to men up to age 26 who have sex with men.
The bivalent vaccine also protects against HPV types 16 and 18, which cause most cervical cancers. It is recommended only for girls and women aged 9 to 25 years old. It is not recommended for boys and men. Three doses are given.
Because of the location of these warts, condoms do not fully protect against infection.
If the immune system is healthy, it often eventually controls HPV and eliminates the warts and the virus, even without treatment. HPV infection is gone after 8 months in half of people and lasts longer than 2 years in fewer than 10%. If people with genital warts have a weakened immune system, treatment is required, and the warts often return.
No treatment for external warts is completely satisfactory, and some treatments are uncomfortable and leave scars. External genital warts may be removed with a laser or an electric current (electrocautery) or by freezing (cryotherapy) or surgery. A local or general anesthetic is used, depending on the number and size of the warts to be removed.
Alternatively, podophyllin toxin, imiquimod, trichloroacetic acid, or sinecatechins (an ointment made from extracts of green tea) can be applied directly to the warts. However, this approach requires many applications over weeks to months, may burn the surrounding skin, and is frequently ineffective. After treatment, the area may be painful. Imiquimod cream causes less burning but may be less effective. The warts may return after apparently successful treatment.
For warts in the urethra, a viewing tube (endoscope) with surgical attachments may be the most effective way to remove them but requires a general anesthetic. Drugs, such as thiotepa inserted into the urethra or the chemotherapy drug 5-fluorouracil injected into the wart, are often effective. Interferon-alpha injections into the wart or into a muscle are somewhat effective, but they must be given several times a week for many weeks and are expensive.
All sex partners should be examined for warts and other STDs and treated, if necessary. Sex partners should also have regular examinations to check for HPV infection.
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