What Are Cold Sores?

Cold sores are caused by a herpes simplex virus, herpes labialis. They occur on or around the mouth, and can also be transmitted to the genital area. The sores are painful blisters that leak fluid then crust over, and they can be accompanied by inflammation of the mouth, fever, sore throat, and other symptoms.

There are a variety of treatments for cold sores. Over-the-counter creams are available, and some prescription drugs used to treat cold sores include herpes virus nucleoside analogues (Valtrex, Denavir, Famvir) and herpes virus nucleoside analogue / corticosteroid combinations (Xerese).