What causes genital herpes?
Genital herpes is caused by a virus—either the herpes simplex virus type 1 or the herpes simplex virus type 2. Either virus can cause sores on the lips (cold sores) and sores on the genitals. Type 1 more often causes cold sores, while type 2 more often causes genital sores.

What are the symptoms?
Symptoms can vary greatly from person to person. Most people never have any symptoms. Sometimes the symptoms are so mild that people may not notice them or recognize them as a sign of herpes. For people who do notice their first infection, it generally appears about 2 to 14 days after they were exposed to genital herpes.

Some people have outbreaks of itchy and painful blisters on the penis or around the opening of the vagina. The blisters rupture and turn into oozing shallow sores that take up to 3 weeks to heal. Sometimes people, especially women, also have flu-like symptoms, such as fever, headache, and muscle aches. They may also notice an abnormal discharge and pain when they urinate.

Genital herpes infections can be severe in people who have impaired immune systems, such as people with HIV.

How is genital herpes diagnosed?
Your doctor may diagnose genital herpes by examining you. He or she may ask you questions about your symptoms and your risk factors, which are things that make you more likely to get a disease.

If this is your first outbreak, your doctor may take a sample of tissue from the sore for testing. Testing can help the doctor be sure that you have herpes. You may also have a blood test.

How is it treated?
Although there is no cure, medicine can relieve pain and itching and help sores heal faster. If you have a lot of outbreaks, you may take medicine every day to keep the number of outbreaks down.

After the first outbreak, some people have just a few more outbreaks over their lifetime, while others may have 4 to 6 outbreaks a year. Usually the number of outbreaks decreases after a few years.

Treatment works best if it is started as soon as possible after the start of an outbreak. This is especially true for outbreaks that come back again and again.

Finding out that you have herpes may cause you to feel bad about yourself or about sex. Counseling or a support group may help you feel better.

Can genital herpes be prevented?
The only sure way to keep from getting genital herpes—or any other sexually transmitted disease (STD)—is to not have sex. If you do have sex, practice safe sex.

•Before you start a sexual relationship, talk with your partner about STDs. Find out whether he or she is at risk for them. Remember that a person can be infected without knowing it.
•If you have symptoms of an STD, don't have sex.
•Don't have sex with anyone who has symptoms or who may have been exposed to an STD.
•Don't have more than one sexual relationship at a time. Having several sex partners increases your risk for disease.
•Use condoms. Condom use lowers the risk of spreading or becoming infected with an STD.
•Don't receive oral sex from partners who have cold sores.
Taking medicine for herpes may lower the number of outbreaks you have and lower the chances that you will infect your partner.

If you are pregnant, you should take extra care to avoid getting infected. You could pass the infection to your baby during delivery, which can cause serious problems for your newborn. If you have an outbreak near your due date, you probably will need to have your baby by cesarean section. If your genital herpes outbreaks return again and again, your doctor may talk to you about medicines that can help prevent an outbreak during pregnancy.

Vaccines that can prevent a genital herpes infection are not available yet, but several are being studied.

Cause
Genital herpes can be caused by either the herpes simplex virus type 1 (HSV-1) or the herpes simplex virus type 2 (HSV-2). HSV-1 or HSV-2 can cause sores on the lips (cold sores ) and sores on the genitals. HSV-1 more often causes cold sores. HSV-2 more often causes genital sores. HSV-1 causes up to 50% of primary genital herpes infections. Genital herpes caused by HSV-1 has a lower rate of recurrence than that caused by HSV-2.1

How the herpes virus is spread
The same virus that causes genital herpes also can cause cold sores (herpes labialis), so HSV can be spread from a genital sore to the lips or from a cold sore to the genital area. HSV can be spread to or from the genitals, anus, or mouth during sexual activities or through any direct contact with herpes sores. You become infected when the virus enters your body through a break in the skin or through moist areas (mucous membranes) such as the mouth, anus, and vagina. Even very small breaks in the skin allow the virus to infect the body.

Newborns can be infected with HSV at birth. This usually happens when a woman has her primary outbreak (the first time she is infected with HSV) close to the time of delivery and the baby is delivered through the vagina. Usually in these cases the woman either does not have symptoms or is unaware of symptoms. The chance of passing the virus to the baby is greatly reduced (less than 1% of the time) during recurrent outbreaks, which occur after a woman has been infected previously.1 Babies infected with the virus at birth are at risk for serious health problems.

Contagious period
You are most likely to spread HSV when you have a sore or blister during either a primary or recurrent outbreak. But many people who have genital herpes have time periods (a week before and a week after an outbreak) when they can spread the virus even though they do not have blisters or sores present. Some people can spread the infection when they do not recognize that they have a genital herpes sore or when they have symptoms (such as painful urination) that are not typical of genital herpes.

Symptoms
Genital herpes symptoms can vary greatly from person to person. Most people never have any symptoms or have ones that are so mild they may not recognize them. But some people have painful and bothersome symptoms. Sometimes the symptoms are confused with other common problems, like yeast infections or vaginosis.

First-time (primary) outbreak
The primary outbreak of genital herpes is the first infection with HSV. It tends to last longer and be more severe than subsequent (recurrent) outbreaks. Symptoms of a primary outbreak may include:

•Flu-like symptoms, such as fever, headache, and muscle aches. These symptoms usually get better within a week.
•Tingling, burning, itching, and redness at the site where an outbreak is about to occur (prodrome).
•Painful, itchy blisters on the penis, on the vulva, or inside the vagina. Blisters may also appear on the anus, buttocks, thighs, or scrotum, either alone or in clusters. They may be barely noticeable or as large as a coin.
•Blisters that break and become shallow, painful, oozing sores.
•Swollen and tender lymph nodes in the groin.
•Painful urination.
•Abnormal vaginal or urethral discharge.
Sometimes a person will first experience symptoms months or even years after being infected. This can make it very difficult to identify the sex partner who was the source of the infection.

Recurrent outbreaks
Recurrent outbreaks of HSV cause painful blisters that rupture, become sores, and heal after 6 to 12 days. Symptoms of recurrent outbreaks are usually limited to genital blisters, sores, and swollen glands. The blisters are most painful during the first 24 hours after they appear. Most people do not have flu-like symptoms with recurrent outbreaks. Recurrent outbreaks are usually less severe and do not last as long as primary outbreaks.

Symptoms of genital herpes infections in both primary and recurrent outbreaks tend to be more severe in women than in men.