What causes a cold sore?

There are two types of herpes simplex virus that can cause cold sores: HSV type 1 and HSV type 2. Cold sores are usually caused by HSV type 1. read more

A fever, a cold, or the flu can leave you feeling run-down and on the defense against a cold sore outbreak. When you feel a cold, fever, or the flu coming on, listen to the experts and get plenty of rest and fluids. read more

Causes. Cold sores are caused by certain strains of the herpes simplex virus (HSV). HSV-1 usually causes cold sores. HSV-2 is usually responsible for genital herpes. However, either type can cause sores in the facial area or on the genitals. Most people who are infected with the virus that causes cold sores never develop signs and symptoms. read more