Cold sores are also known as Herpes Labialis.
A cold sore is a viral infection that affects the skin around the mouth and especially the lips. The first warning signs are the tingling and itching sensation of the affected area. Soon after, the skin starts to swell and redden with a build up of liquid-filled blisters. The blister bursts when mature and the skin dries out. The ulcer caused by the process heals soon after. Normally the symptoms last up to two weeks till full recovery.
The virus Herpes simplex type 1 (HSV 1) is responsible for the infection. Even Herpes simplex type 2, which is usually linked with the genital herpes infection, has been found in this oral infection.Infection usually occurs during childhood and remains dormant in the nerve cells in the skin.
The virus's activity may vary from being dormant and not causing any symptoms for a long time, to recurrent and causing numerous eruptions in a single year.
Remember that cold sores are highly contagious. Avoid contact with newborn babies and with people with immunodeficiency.