Herpes, or herpes simplex, is a viral infection. Mouth (oral) herpes causes blisters, cold sores or a sore throat. Genital herpes is a sexually transmitted infection (STI) that causes sores around the genitals and anus.

By Wallace Health I Medically reviewed by Adrian Roberts.
Page last reviewed: October 2018 I Next review due: October 2023

What is herpes?

Herpes, or herpes simplex, is a viral infection that can affect both men and women.

You can catch herpes through skin-to-skin contact with someone who already has herpes.

In most cases, people don’t immediately know they’ve been infected. It stays in your system and can flare up from time to time. It can’t be cured but you can manage your symptoms. Using a condom during sex can help prevent it from spreading.

In some cases, it can also spread to other parts of the body such as the fingers (known as a whitlow), eyes and brain. If a pregnant woman has herpes, her baby can be infected during birth.

How to tell if you have herpes

Symptoms include:

  • Aches and pains
  • Anal and genital symptoms — this includes: 
  • Having a temperature and feeling unwell
  • Pain when you urinate
  • Sores or blisters that can become ulcers — you may develop sores around your anus, on your buttocks, in your mouth or along your urethra (the tube through which urine drains out of your bladder); men can also develop sores on or in their penis and scrotum; women can also develop sores on or in their cervix, external genitals and vagina
  • Swollen glands in your groin

What does a herpes sore look like?

Herpes sores vary greatly in how they look, they can be small or large and can look different from one outbreak to the next. They are often described as looking like fluid-filled blisters or pimples.

How long does a herpes outbreak last?

Most people don’t know they have herpes when they’re first infected but they can still pass it on to others. It can take weeks, months or years for any symptoms to appear. The virus stays inside your nerves and can flare up from time to time. Herpes symptoms can last from a few days to about a month before slowly going away. 

Talk to your doctor if you’re concerned about symptoms

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Diagnosis and tests for herpes

If you think you may have mouth herpes, your GP will look at any cold sores or other ulcers you may have. In most cases, they won’t need to carry out any further tests. They can treat your symptoms and give you advice about how to avoid passing it on to other people.

If you have symptoms of genital herpes, your GP may suggest you go to a sexual health clinic. They may test for more than one type of STI. The doctor or nurse will take a sample of the discharge from one of the ulcers, using a small cotton bud, to send for analysis. If you don’t have visible ulcers, they can’t perform this test. They will also ask you about your symptoms and your sexual partners. However, they can’t tell you how long you have had herpes or who you contracted it from. 

Causes of herpes

It’s passed on by skin contact, especially from damp areas such as the mouth, anus and genitals. Genital herpes is therefore easily passed on (contagious). You’re most at risk if you have oral, vaginal or anal sex with someone who has oral or genital herpes, or if you share sex toys with someone who has herpes.

If you have a cold sore, you can pass on genital herpes to your partner if you have oral sex or touch their genitals after touching your mouth.

You can pass on herpes even if you don’t have any symptoms. If you do have symptoms, you remain contagious from the first signs of an outbreak (eg itching or tingling) through to when your sores have fully healed and are no longer visible. 

You can’t catch herpes from objects such as cutlery, plates or cups, as the virus does not survive for very long once it is away from a person’s skin.

Types of herpes simplex virus

There are two types of herpes simplex virus (HSV). HSV-1 affects the mouth but can also cause genital herpes. HSV-2 usually only affects the genitals, although it can also cause cold sores.

Herpes simplex virus type 1 (HSV-1)

This is highly contagious, very common and present throughout the world. Most people catch HSV-1 during their childhood and the virus stays with them for life. HSV-1 infections usually cause oral herpes and are called orolabial, oral-labial or oral-facial herpes. However, some HSV-1 infections cause genital herpes.

Herpes simplex virus type 2 (HSV-2)

This is present throughout the world. It is almost always sexually transmitted and causes genital herpes — it is the main cause of genital herpes, which can also be caused by HSV-1. Once infected with HSV-2, it can't be cured and will stay with you for life.

Why does genital herpes come back?

Genital herpes comes back because the herpes virus that causes it stays in your body for life, although it doesn't usually spread everywhere. Instead, it usually stays near a single nerve and causes blisters in the area of your body that this nerve reaches. 

Avoiding triggers for herpes outbreaks can prevent you from having symptoms more often. Common triggers you can avoid include: 

  • Drinking alcohol
  • Friction in your genital area eg from tight clothing or sex (using lubricant during sex may help)
  • Smoking
  • Ultraviolet light eg from sunbathing or sunbeds

Other triggers may not be avoidable; they include: 

  • A weakened immune system eg after chemotherapy for cancer
  • Being unwell or stressed
  • Going through your menstrual cycle
  • Surgery in your genital area

Risk factors

Risk factors for getting genital herpes include: 

  • Being a woman — women get genital herpes more than men as it is more easily passed from men to women than from women to men
  • Have multiple sexual partners — every additional sexual partner increases your risk of being exposed to herpes simplex virus

Common treatments for herpes

There is no herpes cure but treatment can help manage your symptoms.

Your GP may prescribe antiviral medication and some over-the-counter painkillers and creams can also help.

If you have genital herpes, it’s important to let any previous sexual partners know so they can be tested. Your doctor or nurse at a sexual health clinic will talk to you about your sexual partners and can help inform your sexual partners without revealing that it is you who has the virus.

First-time genital herpes treatment

You doctor may prescribe antiviral medication to stop your symptoms worsening. However, you need to start taking this medication within five days of your symptoms first appearing for it to be effective. They may also prescribe a cream to ease any pain. 

If you have had symptoms for more than five days before you see a doctor or nurse, you can still get tested for the virus. 

Treatment for recurring blister outbreaks

If you have been diagnosed with genital herpes and are having a herpes outbreak, see your GP or visit a sexual health clinic. They may prescribe an antiviral medication to shorten the outbreak by one or two days if you visit them as soon as your symptoms occur. However, outbreaks usually get better on their own without the need for treatment. 

Recurrent outbreaks are usually milder than your first outbreak of genital herpes. Over the years, outbreaks tend to occur less and be milder. Some people never have outbreaks.

If you have more then six outbreaks in one year, your doctor may prescribe an antiviral medication that you take for 6-12 months. If you still have outbreaks while on this medication, they may refer you to a specialist. 

Dealing with outbreaks yourself

Make sure you: 

  • Apply an ice pack wrapped in a towel or flannel to reduce your pain
  • Apply petroleum jelly or a painkilling cream (eg 5% lidocaine) to reduce your pain when you urinate
  • Keep the outbreak area clean using plain water or saltwater — this reduces your risk of infection
  • Urinate while pouring water over your genitals to reduce your pain
  • Wash your hands before and after applying any cream or petroleum jelly

Make sure you do not

  • Apply ice directly to your skin
  • Have vaginal, anal or oral sex until your sores have completely gone away
  • Touch your blisters or sores unless you are applying a cream or petroleum jelly
  • Wear tight clothing — this can irritate your blisters or sores

Reducing the risk of spreading herpes

You can reduce the chances of passing on herpes by:

  • Avoiding vaginal, anal or oral sex if you or your partner has the early signs of an outbreak (eg itching or tingling) or has blisters or sores
  • Not sharing sex toys — if you do share sex toys, wash them and place a condom over them
  • Using a condom whenever you have vaginal, anal or oral sex — however, if the condom doesn't cover the infected area, you can still pass on herpes

Treating genital herpes during pregnancy

If you have had herpes and are now pregnant, it is likely you will still have a healthy baby and a vaginal delivery. However, if you have genital herpes during your pregnancy, there is a risk that your baby could develop neonatal herpes, which is a serious and potentially fatal illness. Most babies with neonatal herpes recover if treated with antiviral medication. 

If you have had genital herpes before but do not have genital herpes during your pregnancy, the chances of your baby getting neonatal herpes are low. The risk is higher if you get genital herpes for the first time while pregnant.

If you have had genital herpes or have an outbreak during your pregnancy, you may be prescribed antiviral treatment: 

  • From 36 weeks to reduce the chances of an outbreak during birth
  • From diagnosis until the birth of your baby if you get herpes for the first time after 28 weeks of pregnancy
  • To treat outbreaks during your pregnancy

Many women with genital herpes have a vaginal delivery but you may be offered a caesarean section (C-section), depending on your particular circumstances.

Genital herpes and HIV

If you have HIV and also have genital herpes, it can be more serious and you will be referred to a specialist in genitourinary medicine (GUM).

Complications of genital herpes

  • Bladder problems — genital herpes sores can cause inflammation around your urethra which causes it to swell and close; if the urethra closes you will need a catheter inserted to drain your bladder
  • Meningitis — this is rare; HSV infection can cause inflammation of the membranes and fluid (cerebrospinal fluid) covering your brain and spinal cord
  • Newborn infection — if you are pregnant and have genital herpes, your baby may catch genital herpes during birth; neonatal herpes can cause blindness, brain damage or death of the baby
  • Other sexually transmitted infections (STIs) — genital sores increase your risk of passing on or getting other STIs, including AIDS
  • Rectal inflammation (proctitis) — genital herpes can cause inflammation of the lining of your rectum