Cold sores are small, blister-like lesions which usually appear around the mouth. They're caused by the herpes simplex viruses. The strain that usually causes them around the mouth is herpes simplex type 1 (HSV-1).
In rare cases, cold sores can also be caused by the herpes simplex type 2 virus (HSV-2). This can happen as a result of having oral sex with a man or woman who has genital herpes.
The herpes simplex virus
The herpes simplex virus, or 'cold sore virus', is highly contagious, and can be easily passed from person to person by close direct contact. Once someone has been exposed to the virus it remains dormant (inactive) most of the time.
However, every so often the virus is activated by certain triggers, causing an outbreak of cold sores. The triggers that cause cold sores vary from person to person. Some people have frequently recurring cold sores, two to three times a year for example, whereas others will have one cold sore and then never have another. Some people may never get cold sores at all because the virus never becomes active.
Treating cold sores early
Cold sores usually clear up without treatment in seven to 10 days. Creams and treatments are available over-the-counter (OTC) that can help ease the symptoms of cold sores and to speed up the healing time. To be effective, they must be applied as soon as you have any signs of a cold sore, e.g. pain, burning, tingling, itching or a numb sensation (paraesthesia).
In the majority of cases, cold sores are mild. In rare cases they can cause a number of complications. It isn't possible to prevent cold sores, but there are ways to prevent them from recurring.
