Cold sores are small, blister-like lesions that usually appear around the mouth. They are caused by the herpes simplex viruses, and the strain that usually causes them around the mouth is called herpes simplex type 1 (HSV-1).
In rare cases, cold sores can be caused by 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. It can be passed from person to person by close direct contact. Once someone has been exposed to the virus, most of the time it remains dormant (inactive).
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, for example two or three times a year, while others will have just one cold sore and then never have another. Some people may never get cold sores at all because the virus never becomes active.
Cold sores should be treated early
Cold sores usually clear up without treatment within seven to 10 days. Creams are available over the counter (OTC) to help ease the symptoms of cold sores. Several treatments are also available without a prescription that may help to speed up the healing time. To be effective they must be applied in the early stages of the condition, as soon as you have any signs of cold sores appearing, such as pain or a burning, tingling, itching or numb sensation (paraesthesia).
In most cases cold sores are mild, but in rare cases they can cause a number of complications. It's not possible to prevent cold sores occurring, but there are measures you can take that may prevent them recurring.
