Cold Sore

A painful cluster of tiny blisters, usually near the lips, caused by a viral infection

  • Cold wind, sunburn, and stress are risk factors
  • Age, gender, and genetics are not significant factors

Cold sores are painful clusters of blisters usually caused by herpes simplex virus type 1 (HSV-1). Most people have been infected with HSV-1 at least once by the time they reach adulthood. The initial infection often goes unnoticed but may cause blisters in the mouth. The virus then remains dormant in the nerve cells, but in some people it is reactivated and produces cold sores. Trigger factors include cold wind, sunburn, tiredness, stress, the common cold, menstruation, and fever. Some people have recurrent cold sores.

What are the symptoms?

Cold sores often develop on the skin around the lips. The symptoms usually appear in the following order:

  • The affected site begins to tingle.

  • One or more clusters of tiny, painful blisters develop, and the surrounding skin becomes inflamed.

  • The blisters burst and become crusty.

  • Usually, the blisters subside within 10–14 days.

If cold sores recur, the blisters usually reappear in the same areas on the face.

What might be done?

You may be able to prevent individual outbreaks by using an over-the-counter antiviral cream such as aciclovir (see Preparations for infections and infestations), but you must apply the cream as soon as the first symptoms develop. In some cases, oral antiviral drugs may be prescribed. Although prompt treatment can prevent individual outbreaks, the virus remains in the system and symptoms may recur. If you have recurrent cold sores, try to protect your skin from trigger factors such as sunburn or cold wind. To minimize the risk of spreading the virus, do not touch the blisters and avoid kissing. Sometimes, oral sex can transmit the virus from the mouth to the genitals (see Genital herpes)

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.

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