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Genital Herpes

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Genital herpes is usually a sexually transmitted infection. Many people infected with this virus never have symptoms but can still pass on the infection to others. If symptoms occur, they can range from a mild soreness to painful blisters on the genitals and surrounding area. A first episode of symptoms can last 2-3 weeks but may be shorter. Further (recurrent) episodes then develop in some cases from time to time. These recurrent episodes are usually less severe than the first episode. Antiviral medication can ease symptoms when they develop. Some people who have lots of recurrences of symptoms take this medication each day to prevent symptoms from developing.

Genital herpes is an infection of the genitals (penis in men, vulva and vagina in women) and surrounding area of skin. It is caused by the herpes simplex virus. The buttocks and anus may also be affected. There are two types of herpes simplex virus:

  • Type 1 herpes simplex virus is the usual cause of cold sores around the mouth. It also causes more than half of cases of genital herpes.
  • Type 2 herpes simplex virus usually only causes genital herpes. It can sometimes cause cold sores.

The rest of this leaflet just deals with genital herpes. See separate leaflet called Cold Sores for details about herpes simplex infection around the mouth. Herpes simplex infection can also affect other areas of the body. For example, a herpes simplex infection that develops on a finger is commonly called a whitlow.

Genital herpes is usually passed on by skin-to-skin contact with someone who is already infected with the virus. The moist skin that lines the mouth, genitals and anus is the most susceptible to infection. This means that the virus is most commonly passed on by having vaginal, anal or oral sex, or just close genital contact with an infected person. For example, if you have a cold sore around your mouth, by having oral sex, you may pass on the virus that causes genital herpes.

Herpes simplex virus can also enter through a cut or break in the ordinary skin on other parts of the body. In this way the virus can sometimes affect fingers, hands, knees, etc, if they are in contact with another person's infected area. It is called a whitlow when it is on the fingers.

You are not likely to re-infect yourself with your own virus through accidental touching, or to catch back your own virus from an infected partner, on a different part of your own body.

The first time you are infected with genital herpes simplex it is called the primary infection. This may, or may not, cause symptoms (described below). Following a primary infection, the virus is not cleared from the body but lies inactive (dormant) in a nearby nerve. In some people, the virus 'activates' from time to time and travels down the nerve to the nearby skin. This causes recurrent symptoms of genital herpes if the primary infection was in the genitals, or recurrent cold sores if the primary infection was around the mouth.

It is common not to develop any symptoms

Most people never develop any symptoms when they are infected with the virus. At least 8 in 10 people with genital herpes simplex virus do not know that they are infected. (Or, they only have a short bout of very mild symptoms which is not recognised as genital herpes. For example, just a slight area of itch or a small red area which soon goes.) In such people, the virus stays inactive in the root of a nerve that supplies the genitals, but never causes recurrent episodes of symptoms. However, even people who do not develop symptoms may, on occasions, have virus in their genital area and therefore be infectious to sexual partners. In fact, this is how many genital herpes simplex infections are passed on.

A first episode of symptoms

At first you may feel generally unwell with a mild fever and aches and pains. Groups of small, painful blisters then appear around your genitals and/or anus. They tend to erupt in crops over 1-2 weeks. The blisters soon burst and turn to shallow, sore ulcers. The glands in your groin may swell and feel like lumps at the top of your legs. It is common to have pain when you pass urine, especially in women.

In women, a vaginal discharge may occur. Women may also have blisters and ulcers on the neck of the womb at the top of the vagina (cervix). The inside of the back passage may also be affected. The ulcers and blisters can last up to 10-28 days and then gradually heal and go without scarring.

Sometimes less typical symptoms occur. For example, you may just have a small raw area, one or two small ulcers, or just an area of irritation with nothing to see. Sometimes symptoms last just a few days.

Note: sometimes a first episode of symptoms appears months or years after being first infected. This is why a first episode of symptoms can occur during a current faithful sexual relationship. You may have been infected months or years ago from a previous sexual partner who did not realise that they were infected.

It is not clear why some infected people develop symptoms, some don't and some have a first episode of symptoms months or years after first being infected. It may be something to do with the way the immune system reacts to the virus in different people.

Recurring episodes of symptoms

After the first episode, further episodes of symptoms occur in some people from time to time. This is called recurrent infection. It is not clear why the dormant virus erupts from time to time. Recurrences tend to be less severe and shorter than the first episode. It is more usual to have 7-10 days of symptoms with a recurrence, unlike the longer phase of symptoms that may occur during the first episode. Most people do not develop a fever and do not feel particularly unwell during a recurrence. A tingling or itch in your genital area for 12-24 hours may indicate a recurrence is starting. The time period between recurrences is variable.

Recurrences tend to become less frequent over time. In people who have recurrences, their frequency can vary greatly. Some people have six or more a year. For others it is less frequent than this. On average, people tend to have 1 to 4 recurrences per year during the first two years after the first episode. Some people do not have recurrences at all after a first episode of symptoms. Some people can identify some things that may trigger a recurrence. Such triggers include sunlight, physical illness, excess alcohol, or stress. If you can identify a trigger, it may be helpful to try to avoid this in the future, if possible.

If you suspect that you have genital herpes or any other sexually transmitted infection then see your GP or contact your local genitourinary medicine (GUM) clinic. You can go to the local GUM clinic without a referral from your GP. The websites below include ways to help you find your local clinic. In particular, the Family Planning Association (FPA) and British Association for Sexual Health and HIV (BASHH) websites have "Find your local clinic" sections. Your GP would also be able to advise you where your nearest clinic is.

Yes. A blister can be swabbed by a doctor or nurse to obtain a small sample to send to the laboratory. This can confirm the infection is due to the herpes simplex virus. It may also find out which type of herpes virus has caused the infection. Tests to look for other sexually transmitted infections may also be done at the same time. These swab tests are best carried out in a genitourinary medicine (GUM) clinic. Your GP may sometimes do the tests, but will normally advise you to attend a GUM clinic as soon as possible. You can make an appointment at most GUM clinics yourself without needing a referral from your GP. Sometimes a blood test is done as well. This determines whether you have had a herpes infection in the past, or whether this is the first time. It can also tell which type of herpes simplex virus it is.

General measures that may help to ease symptoms when they occur

  • Painkillers such as paracetamol may help to ease pain.
  • If it is painful when you pass urine, it is often less painful if you pass urine whilst sitting in a warm bath or with water flowing over the area.
  • A numbing (anaesthetic) ointment that you can buy at pharmacies called lidocaine 5% gel may relieve itching or pain. Some people also apply ointment about five minutes before passing urine if this is painful. Note: some people are sensitive (allergic) to anaesthetic ointments, and the ointment then makes skin symptoms worse. Applying Vaseline® before passing urine may be a helpful alternative to anaesthetic ointment.
  • Ice wrapped in a tea towel (an ice pack) placed over the sores for 5-10 minutes may be soothing. Do not put ice directly on to skin, as this may cause an 'ice burn'.
  • Have plenty to drink. This can help to make your urine less strong and less concentrated. This may make passing urine less painful.
  • Do not use scented soaps, bubble bath, etc, as these may irritate. Gentle cleaning of the sores with just cotton wool and plain or salt water is best. Gentle drying with a hairdryer on its lowest setting may be more comfortable than with a towel.
  • When you resume sexual activity after an episode has cleared, a lubricant may help, as some people find the friction of having sex may trigger a recurrence.

Other points:

  • You will not pass on this virus through using towels, facecloths, toilets or swimming pools.
  • You should avoid having sex until the sores and blisters have cleared and/or you have seen a doctor for follow-up.
  • It is best to be honest and tell your sexual partner if you have been diagnosed with genital herpes. If they have not got the infection, the doctor or nurse at the GUM clinic will explain ways to reduce the chances of passing it on to them. The doctor or nurse will also help explain that because of the way the virus works, it is not possible to tell how long ago you acquired the infection. Sometimes people are scared to tell their partners in case their partner thinks they have been unfaithful. Or it may be that they are worried their partner has been unfaithful and given them the infection. But because there is often a long time lag, this is often not the case. Your GUM clinic doctor or nurse will help you with these worries.

Antiviral medication

Antiviral medication does not clear the virus from the body. It works by stopping the virus from multiplying. Antiviral medicines include aciclovir, famciclovir and valaciclovir. Antiviral medication is most useful for a first episode of symptoms. It reduces the severity and duration of symptoms if it is started within five days of symptoms starting. A five-day course of treatment is usual but may be extended by a few days if blisters are still forming.

Antiviral medication may not be needed to treat recurrences. This is because symptoms are often much milder than the first episode and usually last just a few days. However, if you tend to have bad symptoms during recurrences then a course of medication can be useful. To reduce the duration and severity of a recurrence, start the medication as soon as symptoms begin. Some doctors prescribe antiviral medication that you can keep at home and can start at the first sign of a recurrence. Starting treatment early can help to reduce the severity of your symptoms.

If you have frequent recurrences, an option is to take antiviral medication every day. In most people who take medication every day, the recurrences are either stopped completely, or their frequency and severity are greatly reduced. This is called suppressive treatment.

When you have symptoms (during a primary episode or recurrence)

Herpes simplex virus is very contagious when blisters are present. There is a high chance of passing on the virus if you have sex. You should not have sex from the time symptoms first start until they are fully over. If you do have sex, using a condom may not fully protect against passing on the virus, as the condom only protects the area that is covered.

When you do not have symptoms (which is most of the time)

It is less likely that you will pass the virus on when you have sex. However, some virus will be present on the genital skin surface from time to time, although infrequently. So, there is still a small chance that you may pass on the virus when you have sex when you do not have symptoms. It is best to discuss things with your sexual partner. Using a condom each time you have sex is thought to reduce the chance further. However, using a condom cannot completely stop the chance of passing on the virus.

Taking antiviral medication long-term to prevent recurrences (suppressive treatment) also reduces the risk of passing on the virus. However very few people need to take this treatment all the time.

Note: If your sexual partner already has the same virus then you cannot re-infect each other. Your partner may be infected but may not have symptoms. It may be helpful to discuss things with a doctor or nurse at a GUM clinic.

In a small number of people the infection can spread to other areas of skin on the body. Occasionally, the blisters become infected by other germs (bacteria) to cause a spreading skin infection. Note: genital herpes does not damage the womb (uterus) or cause infertility. Nor does it cause cancer of the cervix.

A specialist will normally advise about what to do if you develop genital herpes whilst you are pregnant, or if you have recurrent genital herpes and become pregnant. This is because there may be a chance of passing on the infection to your baby.

A first episode of genital herpes whilst you are pregnant

If you develop a first episode of genital herpes within the last six weeks of your pregnancy, or around the time of the birth, the risk of passing on the virus to your baby is highest (there is about a 4 in 10 chance). The baby may develop a very serious herpes infection if he or she is born by a vaginal delivery.

Therefore, in this situation your specialist is likely to recommend that you have a caesarean section delivery. This will greatly reduce the chance that the baby comes into contact with the virus (which is mainly in the blisters and sores around your genitals). Infection of the baby is then usually (but not always) prevented.

However, if you decide against a caesarean and opt for a vaginal birth, the specialist is likely to recommend that you be given antiviral medication (usually aciclovir). This is given into your veins (intravenously) during your labour and birth. They may also suggest that antiviral medication should be given to your baby after he or she is born.

If you develop a first episode of herpes infection during the first stages of your pregnancy, there is not thought to be any extra risk of miscarriage or of abnormalities in the baby.

As long as there are two months between your catching the virus and the birth of your baby, a normal vaginal delivery is likely to be safe for the baby. This is because there will be time for your body to produce protective proteins called antibodies. These are passed on to the baby through your bloodstream to protect it when it is being born. The specialist may advise that you should be treated with antiviral medication at the time of infection. This helps the sores to clear quickly. In addition, your doctor may advise that you should take antiviral medication in the last four weeks of pregnancy to help prevent a recurrence of herpes at the time of childbirth. Antiviral medicines such as aciclovir have not been found to be harmful to the baby when taken during pregnancy.

If you have recurrent genital herpes and become pregnant

If you have recurring episodes of genital herpes, the risk to your baby is low. Even if you have an episode of blisters or sores during childbirth, the risk of your baby developing a serious herpes infection is low. This is because you pass on some antibodies and immunity to the baby during the last two months of pregnancy.

For most women with recurrent genital herpes, it is felt to be safe to have a normal vaginal delivery. This is even the case if you have a recurrence whilst giving birth. However, you and your specialist will weigh up the pros and cons of vaginal delivery vs caesarean section. If you do have a recurrent episode when you go into labour, you should discuss your options with your specialist and together decide the best way that your baby should be delivered.

Often antiviral medication will be advised in the last four weeks running up to childbirth. This may help to prevent a recurrence of blisters during childbirth. Again, your specialist will be able to advise on the pros and cons.

In summary

A first episode of herpes around the time of birth can be serious for the baby and a caesarean section is usually advised. In any other situation - an earlier primary infection or a history of recurrent episodes - the risk to the baby is low and your specialist will advise on possible options.

There is not yet a vaccine to protect against the herpes virus. There are a number of things to consider which may reduce your risks of getting genital herpes or of passing it on to others. These include:

  • Consider the use of condoms always, even in settled relationships. This is because a person can carry the herpes virus for a very long time and pass it on without ever being aware of it. Condoms do not completely protect against herpes but they reduce the risk.
  • The more sexual partners you have, the more the risk of picking up any sexually transmitted infection, including herpes. So avoiding having too many partners will cut down your risk.
  • Avoid having sex with somebody with an active genital herpes infection (ie somebody with visible genital sores or blisters).
  • Also avoid intimate contact with a person who has a cold sore.
  • If you have an active herpes infection yourself, avoid having sex with anyone else in order to prevent passing it on.
  • If one partner finds out they have herpes, it is wise to tell the other. This can reduce transmission rates.
  • If a person knows they have recurrent herpes, taking a regular antiviral medicine can reduce the risk of passing on the virus.
  • In particular, a pregnant woman should avoid having sex with somebody with active herpes, because of the extra risk to the baby during delivery.
Original Author:
Dr Tim Kenny
Current Version:
Peer Reviewer:
Dr Helen Huins
Document ID:
4255 (v45)
Last Checked:
Next Review:
The Information Standard - certified member
See also: Genital Herpes Simplex written for professionals
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