Human Papillomavirus and Genital Warts
What is human papillomavirus?
Human papillomavirus (HPV) is one of the most common causes of sexually
transmitted infection (STI) in the world. Health experts estimate that
there are more cases of genital HPV infection than of any other STI in
the United States. According to the American Social Health Association,
approximately 5.5 million new cases of sexually transmitted HPV infections
are reported every year. At least 20 million Americans are already infected.
Scientists have identified more than 100 types of HPV, most of which
are harmless. About 30 types are spread through sexual contact. Some
types of HPV that cause genital infections can also cause cervical cancer
and other genital cancers.
Like many STIs, genital HPV infections often do not have visible signs
and symptoms. One study sponsored by the National Institute of Allergy
and Infectious Diseases (NIAID) reported that almost half of the women
infected with HPV had no obvious symptoms. People who are infected but
who have no symptoms may not know they can transmit HPV to others or
that they can develop complications from the virus.
What are genital warts?
Genital warts (condylomata acuminata or venereal warts) are the most easily
recognized sign of genital HPV infection. Many people, however, have a
genital HPV infection without genital warts.
Can HPV cause other kinds of warts?
Some types of HPV cause common skin warts, such as those found on the
hands and soles of the feet. These types of HPV do not cause genital warts.
How are genital warts spread?
Genital warts are very contagious and are spread during oral, genital,
or anal sex with an infected partner. About two-thirds of people who have
sexual contact with a partner with genital warts will develop warts, usually
within three months of contact.
In women, the warts occur on the outside and inside of the vagina,
on the opening (cervix) to the womb (uterus), or around the anus. In
men, genital warts are less common. If present, they usually are seen
on the tip of the penis. They also may be found on the shaft of the
penis, on the scrotum, or around the anus. Rarely, genital warts also
can develop in the mouth or throat of a person who has had oral sex
with an infected person.
Genital warts often occur in clusters and can be very tiny or can spread
into large masses in the genital or anal area.
How are genital warts diagnosed?
A doctor or other health care worker usually can diagnose genital warts
by seeing them on a patient. Women with genital warts also should be examined
for possible HPV infection of the cervix.
The doctor may be able to identify some otherwise invisible warts in
the genital tissue by applying vinegar (acetic acid) to areas of suspected
infection. This solution causes infected areas to whiten, which makes
them more visible, particularly if a procedure called colposcopy is
performed. During colposcopy, the doctor uses a magnifying instrument
to look at the vagina and cervix. In some cases, the doctor takes a
small piece of tissue from the cervix and examines it under the microscope.
A Pap smear test also may indicate the possible presence of cervical
HPV infection. In a Pap smear, a laboratory worker examines cells scraped
from the cervix under a microscope to see if they are cancerous. If
a woman’s Pap smear is abnormal, she might have an HPV infection. If
a woman has an abnormal Pap smear, she should have her doctor examine
her further to look for and treat any cervical problems.
What is the treatment for genital warts?
Genital warts often disappear even without treatment. In other cases,
they eventually may develop a fleshy, small raised growth that looks like
cauliflower. There is no way to predict whether the warts will grow or
disappear. Therefore, if you suspect you have genital warts, you should
be examined and treated, if necessary.
Depending on factors such as the size and location of the genital warts,
a doctor will offer you one of several ways to treat them.
- Imiquimod, an immune response cream which you can apply to the affected
- A 20 percent podophyllin anti-mitotic solution, which you can apply
to the affected area and later wash off
- A 0.5 percent podofilox solution, applied to the affected area but
shouldn’t be washed off
- A 5 percent 5-fluorouracil cream
- Trichloroacetic acid (TCA)
If you are pregnant, you should not use podophyllin or podofilox because
they are absorbed by the skin and may cause birth defects in your baby.
In addition, you should not use 5-fluorouracil cream if you are expecting.
If you have small warts, the doctor can remove them by freezing (cryosurgery),
burning (electrocautery), or laser treatment. Occasionally, the doctor
will have to use surgery to remove large warts that have not responded
to other treatment.
Some doctors use the antiviral drug alpha interferon, which they inject
directly into the warts, to treat warts that have returned after removal
by traditional means. The drug is expensive, however, and does not reduce
the rate that the genital warts return.
Although treatments can get rid of the warts, none gets rid of the
virus. Because the virus is still present in your body, warts often
come back after treatment.
How can HPV infection be prevented?
The only way you can prevent getting an HPV infection is to avoid direct
contact with the virus, which is transmitted by skin-to-skin contact.
If you or your sexual partner have warts that are visible in the genital
area, you should avoid any sexual contact until the warts are treated.
Studies have not confirmed that male latex condoms prevent transmission
of HPV itself, but results do suggest that condom use may reduce the risk
of developing diseases linked to HPV, such as genital warts and cervical
Can HPV and genital warts cause complications?
Some types of HPV can cause cervical
cancer. Others, however, cause cervical cancer and also are associated
with vulvar cancer, anal cancer, and cancer of the penis (a rare cancer).
Most HPV infections do not progress to cervical cancer. If a woman
does have abnormal cervical cells, a Pap test will detect them. It is
particularly important for women who have abnormal cervical cells to
have regular pelvic exams and Pap tests so that they can be treated
early, if necessary.
Pregnancy and Childbirth
Genital warts may cause a number of problems during pregnancy. Sometimes
they get larger during pregnancy, making it difficult to urinate. If
the warts are in the vagina, they can make the vagina less elastic and
cause obstruction during delivery.
Rarely, infants born to women with genital warts develop warts in their
throats (laryngeal papillomatosis). Although uncommon, it is a potentially
life-threatening condition for the child, requiring frequent laser surgery
to prevent obstruction of the breathing passages. Research on the use
of interferon therapy in combination with laser surgery indicates that
this drug may show promise in slowing the course of the disease.
What research is going on?
Scientists are doing research on two types of HPV vaccines. One type would
be used to prevent infection or disease (warts or pre-cancerous tissue
changes). The other type would be used to treat cervical cancers. Researchers
are testing both types of vaccines in people.
Where can I get more information?
American Social Health Association
P.O. Box 13827
Research Triangle Park, NC 27709
Toll-free: 1-877-HPV-5868 (1-877-478-5868) (2:00 p.m. to 7:00 p.m. ET)
1-800-4 CANCER (1-800-422-6237)
NIAID is a component of the National Institutes of Health
(NIH), which is an agency of the Department of Health and Human Services.
NIAID supports basic and applied research to prevent, diagnose, and
treat infectious and immune-mediated illnesses, including HIV/AIDS
and other sexually transmitted diseases, illness from potential agents
of bioterrorism, tuberculosis, malaria, autoimmune disorders, asthma
News releases, fact sheets and other NIAID-related
materials are available on the NIAID Web site at http://www.niaid.nih.gov.
Office of Communications and Public Liaison
National Institute of Allergy and Infectious Diseases
National Institutes of Health
Bethesda, MD 20892
Last Updated November 21, 2003 (alt)