Genital herpes is an infection caused by the herpes simplex virus or HSV. There are two types of HSV, and both can cause genital herpes. HSV type 1 most commonly infects the lips, causing sores known as fever blisters or cold sores, but it also can infect the genital area and produce sores. HSV type 2 is the usual cause of genital herpes, but it also can infect the mouth. A person who has genital herpes infection can easily pass or transmit the virus to an uninfected person during sex.

Both HSV 1 and 2 can produce sores (also called lesions) in and around the vaginal area, on the penis, around the anal opening, and on the buttocks or thighs. Occasionally, sores also appear on other parts of the body where the virus has entered through broken skin.

HSV remains in certain nerve cells of the body for life, and can produce symptoms off and on in some infected people.

According to the U.S. Centers for Disease Control and Prevention, 45 million people in the United States ages 12 and older, or 1 out of 5 of the total adolescent and adult population, are infected with HSV-2.

Nationwide, since the late 1970s, the number of people with genital herpes infection has increased 30 percent. The largest increase is occurring in young teens. HSV-2 infection is more common in three of the youngest age groups which include people aged 12 to 39 years.

Most people get genital herpes by having sex with someone who is having a herpes "outbreak." This outbreak means that HSV is active. When active, the virus usually causes visible lesions in the genital area. The lesions shed (cast off) viruses that can infect another person. Sometimes, however, a person can have an outbreak and have no visible sores at all. People often get genital herpes by having sexual contact with others who don't know they are infected or who are having outbreaks of herpes without any sores.

A person with genital herpes also can infect a sexual partner during oral sex. The virus is spread only rarely, if at all, by touching objects such as a toilet seat or hot tub.

Unfortunately, most people who have genital herpes don't know it because they never have any symptoms, or they do not recognize any symptoms they might have. When there are symptoms, they can be different in each person. Most often, when a person becomes infected with herpes for the first time, the symptoms will appear within 2 to 10 days. These first episodes of symptoms usually last 2 to 3 weeks.

Early symptoms of a genital herpes outbreak include

Itching or burning feeling in the genital or anal area
Pain in the legs, buttocks, or genital area
Discharge of fluid from the vagina
Feeling of pressure in the abdomen

Within a few days, sores appear near where the virus has entered the body, such as on the mouth, penis, or vagina. They also can occur inside the vagina and on the cervix in women, or in the urinary passage of women and men. Small red bumps appear first, develop into blisters, and then become painful open sores. Over several days, the sores become crusty and then heal without leaving a scar.

Other symptoms that may go with the first episode of genital herpes are fever, headache, muscle aches, painful or difficult urination, vaginal discharge, and swollen glands in the groin area.

If you have been infected by HSV 1 and/or 2, you will probably have symptoms or outbreaks from time to time. After the virus has finished being active, it then travels to the nerves at the end of the spine where it stays for a while. Even after the lesions are gone, the virus stays inside the nerve cells in a still and hidden state, which means that it's inactive.

In most people, the virus can become active several times a year. This is called a recurrence. But scientists do not yet know why this happens. When it becomes active again, it travels along the nerves to the skin, where it makes more viruses near the site of the very first infection. That is where new sores usually will appear.

Sometimes, the virus can become active but not cause any sores that can be seen. At these times, small amounts of the virus may be shed at or near places of the first infection, in fluids from the mouth, penis, or vagina, or from barely noticeable sores. You may not notice this shedding because it often does not cause any pain or feel uncomfortable. Even though you might not be aware of the shedding, you still can infect a sex partner during this time.

After the first outbreak, any future outbreaks are usually mild and last only about a week. An infected person may know that an outbreak is about to happen by a tingling feeling or itching in the genital area, or pain in the buttocks or down the leg. For some people, these early symptoms can be the most painful and annoying part of an episode. Sometimes, only the tingling and itching are present and no visible sores develop. At other times, blisters appear that may be very small and barely noticeable, or they may break into open sores that crust over and then disappear.

The frequency and severity of recurrent episodes vary greatly. While some people have only one or two outbreaks in a lifetime, others may have several outbreaks a year. The number and pattern of repeat outbreaks often change over time for a person. Scientists do not know what causes the virus to become active again. Although some people with herpes report that their outbreaks are brought on by another illness, stress, or having a menstrual period, outbreaks often are not predictable. In some cases, outbreaks may be connected to exposure to sunlight.

Because the genital herpes sores may not be visible to the naked eye, a doctor or other health care worker may have to do several laboratory tests to try to prove that symptoms are caused by the herpes virus. A person may still have genital herpes, however, even if the laboratory tests do not show the virus in the body.

A blood test cannot show whether a person can infect another with the herpes virus. A blood test, however, can show if a person has been infected at any time with HSV. There are also newer blood tests that can tell whether a person has been infected with HSV 1 and/or 2.

Although there is no cure for genital herpes, your health care worker might prescribe one of three medicines to treat it as well as to help prevent future episodes.

Acyclovir (Zovirax)
Famciclovir (Famvir)
Valacyclovir (Valtrex)

Recently, the Food and Drug Administration approved Valtrex for use in preventing transmission of genital herpes.

During an active herpes episode, whether the first episode or a repeat one, you should follow a few simple steps to speed healing and avoid spreading the infection to other places on the body or to other people.

Keep the infected area clean and dry to prevent other infections from developing.
Try to avoid touching the sores.
Wash your hands after contact with the sores.
Avoid sexual contact from the time you first feel any symptoms until the sores are completely healed, that is, the scab has fallen off and new skin has formed where the sore was.

Usually, genital herpes infections do not cause major problems in healthy adults. In some people whose immune systems do not work properly, genital herpes episodes can last a long time and be unusually severe. (The body's immune system fights off foreign invaders such as viruses.)

If a woman has her first episode of genital herpes while she is pregnant, she can pass the virus to her unborn child and may deliver a premature baby. A baby born with herpes can develop serious problems that may affect the brain, the skin, or the eyes. If babies born with herpes are treated immediately with acyclovir, their chances of being healthy are increased.

If a pregnant woman has an outbreak, which is not the first episode, her baby's risk of being infected during delivery is very low. In either case, if you are pregnant and infected with genital herpes, you should stay in close touch with your doctor before, during, and after your baby is born.

If a woman is having an outbreak during labor and delivery and there are herpes lesions in or near the birth canal, the doctor will do a cesarean section to protect the baby. Most women with genital herpes, however, do not have signs of active infection with the virus during this time, and can have a normal delivery.

Genital herpes, like other genital diseases that produce lesions, increases a person's risk of getting HIV, the virus that causes AIDS. Also, prior to better treatments for AIDS, persons infected with HIV had severe herpes outbreaks, which may have helped them pass both genital herpes and HIV infection to others.