Genital herpes: what it is, symptoms and treatment

Genital herpes is a sexually transmitted infection caused by the herpes simplex virus (HSV). There is no cure, because the virus stays in the body for life, but it can be treated and controlled very well with antiviral medicine. It is very common: according to the World Health Organization (WHO), around 846 million people aged 15 to 49 live with genital herpes, more than 1 in 5 adults worldwide.

What it is and what causes it

There are two types of the virus: HSV-1 and HSV-2. HSV-1 usually causes cold sores and is often picked up in childhood. HSV-2 is almost always passed on through sex and causes most outbreaks. But HSV-1 can also reach the genitals through oral sex. WHO estimates there are around 42 million new infections every year.

After the first infection, the virus settles in the nerves of the area and lies dormant. From time to time it can wake up and cause a new outbreak, or reach the skin without causing any symptoms.

Symptoms and when they appear

Most people have no symptoms, or such mild ones that they mistake them for a spot, an ingrown hair or a bit of chafing. That is why many people do not know they have the virus. Symptoms can take weeks, months or even years to appear.

During an outbreak, the usual signs are:

• tingling, itching or burning in the area before anything shows;
• small blisters that burst and leave painful sores on the genitals, anus, thighs or bottom;
• pain or stinging when you pee;
• with the first outbreak, sometimes a temperature, feeling unwell and swollen glands, like flu.

Sores can take a week or more to heal. Later outbreaks are usually shorter and milder, and they tend to become less frequent over the years. Some people never have another one.

How it spreads – and how it doesn't

Herpes spreads through skin-to-skin contact during vaginal, anal or oral sex. A cold sore can pass to the genitals during oral sex, and the other way round. It can also spread via fingers, or by sharing sex toys that have not been washed or covered.

The risk is highest from the first tingling until the sores have fully healed. But the virus can also be passed on when there are no symptoms or visible sores.

Herpes is not spread by toilet seats, towels, bedding, swimming pools, saunas, soap or cutlery.

Testing: when and how

If you have a sore, it is best to be seen while it is still active. A clinician takes a swab and sends it to the lab (a PCR test). This is the most reliable test. If the sore is already healing, the result can be negative even if it is herpes.

There is also a blood test that looks for antibodies. It has limits:

• antibodies take a few weeks to appear, so a recent infection may not show up; the CDC advises repeating the test about 12 weeks after the possible exposure;
• it cannot tell you when or from whom you got the virus;
• it is not recommended as a routine screening test for people without symptoms.

Herpes is not always part of a standard STI screen. To find out which tests to ask for and how often, read how often to get tested for STIs.

Treatment: controlled, not cured

Antiviral medicine eases an outbreak and makes it shorter, especially if you start it early, within the first few days. If outbreaks are frequent, a clinician may suggest daily treatment (suppressive therapy). This greatly reduces the number of outbreaks and also lowers the chance of passing the virus to a partner.

During an outbreak, it helps to keep the area clean and dry, wear loose clothing and take painkillers if needed. Your clinician will always decide the exact treatment.

When can you have sex again? Avoid vaginal, anal and oral sex from the first tingle until the sores have completely healed.

Complications and pregnancy

For most people, genital herpes does not cause serious problems. But there are two things worth knowing:

• Sores make it easier for HIV to get in. WHO says HSV-2 is linked to around a threefold higher risk of getting HIV. If you have herpes, an HIV test and a chat about PrEP are a good idea. Find out more on our HIV page.
• In people with a very weak immune system, outbreaks can be stronger and last longer.

In pregnancy, people who had herpes before usually have a normal birth and a healthy baby. The risk to the baby (neonatal herpes, rare but serious) is higher if the infection is caught for the first time late in pregnancy, or if there is an outbreak during labour. Tell your midwife or doctor: they may offer antivirals in the last weeks and, if there are sores at the birth, a caesarean. There is more in our pregnancy and postpartum guide.

Prevention

• Condoms lower the risk but don't remove it: the virus can be on skin they don't cover. Use one properly from the start; check the most common condom mistakes.
• Avoid sexual contact during outbreaks, and avoid oral sex if you have a cold sore.
• If your partner has herpes, their taking daily antiviral medicine lowers the risk for you.
• Talking about it calmly with a partner helps you decide together and takes away a lot of worry.

At present there is no vaccine against genital herpes.

When to get help

Book an appointment with your GP or a sexual health clinic if:

• you notice blisters, sores or broken skin on your genitals or anus, even if you haven't had sex for a long time;
• your outbreaks are frequent or very uncomfortable;
• you are pregnant and have or have had herpes, or your partner has it;
• you have a weakened immune system.

You will be seen without judgement and helped to find the treatment that suits you best.