Cold sore is an infection caused by Herpes simplex viruses. This infection is highly contagious and passed on through skin-to-skin contact. The viruses infect when the person is exposed to person with active lesion. These viruses enter through lips and attack the nerve cell of the body then these viruses travel towards the ganglia. In the ganglia viruses take rest and when triggered are activated. Presence of the viruses can be observed through the out breaking of blisters or cold sores near mouth and nose area. Out breaking of cold sores includes burning, itching and tingling of the area. Subsequent to this within few hors this area becomes red with small stick and honey colored fluid filled blisters occurs on that area. Frequently all these small blister together makes a large blisters.
