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Cold sore on the outside of a mouth.

Cold sore on the outside of a mouth.
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Cold sores

Cold sores are small blister-like spots that appear in or around the outside of the mouth. Cold sores are caused by a virus, known as herpes simplex type 1 (HSV-1). About 80 per cent of adults are infected with the virus. Most people are infected when they are young and the infection lasts for life. However the virus can remain dormant (inactive) in some people, meaning that cold sores may never appear.

However, there are various factors that can cause the virus to become active resulting in one or more cold sores. They can include:

  • tiredness and fatigue
  • a break in the skin near the affected area
  • periods (menstruation)
  • emotional upsets or stress
  • strong sunlight, cold or wind
  • alcohol
  • colds, flu or fevers that make the body less able to fight off infection.

Cold sores start with an itchy and tingling sensation usually on the mouth, lips or nose (and can form on the genitals) and may form small blisters which crust after 3 days.

Cold sores usually clear up after 7-10 days without leaving any scars. However, they can be highly contagious, even when the blisters aren’t present. The virus can spread between people by direct physical contact, such as kissing, skin to skin contact, sharing drink containers or eating utensils, towels or toothbrushes with someone who already has a cold sore.

As well as a blister-like spot, the following symptoms are also common:

Your pharmacist may recommend products to treat the short term symptoms of a cold sore.

Not sure what to do next?

If you are still concerned about your cold sores, why not use healthdirect’s online Symptom Checker to get advice on when to seek medical attention.

The Symptom Checker guides you to the next appropriate healthcare steps, whether it’s self care, talking to a health professional, going to a hospital or calling triple zero (000).

Last reviewed: November 2016

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Cold sores overview - myDr.com.au

A cold sore is a skin infection that is caused by the herpes simplex virus (HSV). Cold sores usually occur on or around the lips or nose and are very common. They have nothing to do with colds.

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Most of us have had a cold sore or seen a cold sore at some time in our lives. Cold sores are common skin sores that usually form on the lips or skin around the mouth. They are caused by a virus (herpes simplex type 1), which is often passed on to us when we are children.

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Cold sore infections - myDr.com.au

Find the answers to common questions about cold sores, irritating blisters which are caused by the herpes simplex type 1 virus and can be triggered by stress, fatigue or exposure to sunlight.

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Cold sores are caused by a virus called herpes simplex virus (HSV). Cold sores are very common. About 20% of children will have been infected by theage of 5 years and about80% of people will have been infected by the time they are adults.

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Cold sores are quite common in older children and adults. Cold sores usually clear up by themselves, but see your GP if youre concerned.

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Herpes simplex virus type 1 (HSV1) causes cold sores on the face or lips - it is spread by skin or mucous membrane contact with infected saliva

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There are two types of herpes, which cause small, painful blisters. One causes cold sores and is spread through kissing. The other mainly causes genital sores and is spread through sexual contact.

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Find out the truth about some common myths surrounding genital herpes involving cervical cancer, condoms, cold sores and oral sex.

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No, you haven't got the plague, but if you are a school kid you may have a pimple, or a cold sore, or you may have impetigo (say im-pet-eye-go).

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