What is a cold sore?
A cold sore is a small, painful, raised area of small, fluid-filled blisters. They usually happen where the lip joins the surrounding skin. The blisters are painful and dry up to make a yellow crust which gradually heals in a few days. Cold sores are usually found on the lips but you can get them in other places, such as in the nostrils, on the nose or around the outside of the mouth. Cold sores tend to last 5 to 7 days and can keep coming back. Most people only have them once or twice a year.
How do I get cold sores?
Cold sores are caused by a virus (a ‘Herpes Simplex’ virus). You first get this virus in childhood or early adulthood, and it may cause a fever and mouth ulcers. About a third of people who get this ‘primary’ infection go on to develop cold sores in later life. However, many people with cold sores did not get this primary infection.
What brings on the cold sores?
Cold sores usually appear when people are ‘run down’, or ill with something else: for example, with a cold or flu. Sunlight and ultraviolet light can often bring on an attack of cold sores. Occasionally women find that they develop cold sores at particular stages of their menstrual cycle.
Are they infectious?
Yes. Cold sores are infectious and the virus can be passed to other people by close contact (such as kissing). A cold sore is most infectious when it is blistering. It is important to try to avoid touching cold sores, because you can pass the virus on to other people’s hands and even, very rarely, to your own eyes. Avoid squeezing, pinching or pricking the cold sore as this can spread the infection.
Can they be treated?
Yes. Antiviral creams, such as Aciclovir to ease the pain and blistering and help the sores heal more quickly. You can buy Aciclovir from a pharmacist. You need to use these creams as early as possible when the cold sore starts to develop, and you should apply your cream regularly.