Most cold sores are caused by the herpes simplex virus type 1 (HSV-1), as opposed to herpes simplex virus type 2 (HSV-2), which is typically responsible for genital herpes. HSV-1 or -2 are often spread through close human contact, such as kissing or oral sex, but it can also be caused by sharing razors, towels, utensils, or other small accessories or appliances that involve your hands and face. However, HSV-1 does not always cause cold sores. For a cold sore outbreak to happen as a result of HSV-1, there are a number of different factors that can trigger the sores, such as the following: • Common cold, fever, influenza, or another illness • Compromised immune system or immune system changes • Dental trauma • Exposure to a hot sun, a cold wind, or cold weather • Fatigue • Fluctuating hormone levels, often due to menstruation • Skin injury • Stress It should also be noted that a canker sore is not the same thing as a cold sore. Whereas cold sores appear outside the mouth and are contagious, canker sores occur inside the mouth and are not infectious. If you are dealing with a canker sore and are at your wits’ end about it, please do not hesitate to come and see our medical experts at Immediate Care of Oklahoma! Our board-certified physicians would be happy to see you for a walk-in appointment at any of our seven different locations in Oklahoma City, Edmond, Norman, and Yukon, Oklahoma.