A cold sore is an infection, which is caused by an organism, called the herpes simplex virus (HSV). This virus is different from the one that causes colds. Although most of the population carries the virus, not everyone gets attacks of cold sores or fever blisters, as they are sometimes known. However, one in four people do get repeated attacks. It is not uncommon to have between one and six attacks a year.

The first infection usually occurs in early childhood probably after being kissed by a person with a cold sore – for example a parent or other adult, brother or sister. The virus passes through the skin, travels up a nerve and then hides in a nerve junction until reactivated.

The cold sore virus returns down the nerve to the face where it starts to replicate – causing the tingling sensation. If not treated, the virus replication results in the formation of a cold sore blister.

Triggers for cold sore attacks can include the following: menstruation, emotional upset and stress, bright sunlight and wind, stomach upset, fatigue, physical injury or just feeling a bit run down. There are also dietary triggers. Foods high in L-Arginine such as pork, chocolate and peanuts are notorious for triggering cold sore attacks. I once conducted an informal survey of clients presenting for cold sore treatments. Seven out of ten told me that they had either chocolate or peanuts or both in the few days prior to a cold sore attack.

Cold sores are infectious. Always wash your hands after touching cold sores or after applying medication to them. Avoid touching the eyes – it is possible to get the virus in the eyes and it can be a serious problem. For the same reason never use saliva to wet a contact lens. Avoid kissing while you have a cold sore.

Cold sores can be treated with anti-viral creams such as Zovirax or Vectavir. Both these creams are not suitable for use if you are pregnant. A relatively new treatment, the Compeed Cold Sore Patch works as effectively as the creams and may offer some cosmetic advantages not found with the creams.