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Cold sore

Cold sores are usually caused by the herpes simplex virus type 1 (HSV-1). Occasionally, they can also be caused by the herpes simplex virus type 2 (HSV-2).

Cold sores are usually caused by the herpes simplex virus.

In most cases the virus is passed on in early childhood – for example, when a child is kissed by a family member or friend with a cold sore.

The virus passes through the skin and travels up the nerves, where it lies inactive (dormant) until it's triggered at a later date.

Cold sore triggers

Factors thought to trigger outbreaks of cold sores include:

  • having another infection, such as a respiratory tract infection
  • having a high temperature (fever)
  • emotional upset or psychological stress
  • tiredness and fatigue
  • an injury to the affected area
  • menstruation (periods)
  • strong sunlight

However, in many cases there's no obvious trigger for an outbreak.

Genital herpes

Cold sores can happen after having oral sex with a man or woman who has genital herpes.


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Your Neighbourhood Professionals Need care but want to stay in your own home? Royal Arsenal Psychological Services Dr Anindita Sarkar Temple Pharmacy Ltd
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