Causes of genital herpes 

Genital herpes is caused by the herpes simplex virus (HSV). The virus is highly contagious and spreads from one person to another through skin-to-skin contact, such as during vaginal, anal or oral sex.

There are two types of HSV:

  • type 1 (HSV-1)
  • type 2 (HSV-2)

Genital herpes is caused by both type 1 and type 2 HSV.

Whenever HSV is present on the surface of your skin it can be passed on to a partner. The virus passes easily through the moist skin that lines your genitals, mouth and anus (the opening where solid waste leaves the body).

In some cases it is also possible to become infected by coming into contact with other parts of the body that can be affected by HSV, such as the eyes and skin. For example, you can catch genital herpes if you have oral sex with someone who has a cold sore. A cold sore is a blister-like lesion around the mouth that is also caused by HSV.

Genital herpes cannot usually be passed on through objects, such as towels, cutlery or cups because the virus dies very quickly when away from your skin. However, you may become infected by sharing sex toys with someone who has the virus.

Genital herpes is particularly easy to catch when an infected person has blisters or sores. However, it can be caught at any time, even when someone has no symptoms at all.

Once you have been infected with HSV, it can be reactivated every so often to cause a new episode of genital herpes. This is known as recurrence.

Recurrence triggers

It is not completely understood why HSV is reactivated, but certain triggers may be responsible for the symptoms of genital herpes recurring.

For example, friction in your genital area during sexual intercourse may cause a recurrence. Using a lubricant can help – these are available from pharmacies without needing a prescription.

Other possible triggers include:

  • being unwell
  • stress
  • drinking excess amounts of alcohol
  • exposure to ultraviolet light, for example, using sunbeds
  • surgery on your genital area
  • having a weakened immune system (the body’s natural defence system), for example, as a result of having chemotherapy (treatment for cancer)



Risk factors

You are at increased risk of getting genital herpes and other sexually transmitted infections (STIs) if you:

  • have had an STI before
  • started having sex at a young age
  • have unprotected sex with many different partners

Page last reviewed: 22/08/2014

Next review due: 22/08/2016