Cold sores are small blisters or lesions on the skin. They usually form around the mouth, and are caused by the herpes simplex virus, or HSV. Before the sores appear there may be a tingling, itching or burning sensation on the skin.
After a few days, the blisters can burst and form a crust. The virus that causes cold sores, can be spread to other parts of the body. This often happens through direct contact with blisters, or by saliva from an infected person. Once infected, the same virus can cause symptoms to appear again. If you have HSV, an outbreak may be triggered by having a cold or the flu, over exposure to sunlight, windy conditions, menstruation or stress.
Antiviral creams or tablets may help reduce the severity of an outbreak. Especially if applied at the first sign of symptoms. Avoiding known triggers may also help reduce the frequency of outbreaks.