Labial herpes is caused by the herpes zoster virus. Approximately 80–90% of the population carries and is infected by this virus, and many don’t know it and never present symptoms.
After the initial infection the virus can remain dormant for years, decades, or even a lifetime. However, the virus does occasionally become active, causing what are commonly called "cold sores." It starts with a tingling sensation on the lips, followed by lesions that break and scab over. Cold sores usually heal within a few days. The virus is easily transmitted from one person to another by direct contact with the skin or saliva of an infected person. We don’t know why the virus becomes active and causes labial herpes in some people and remains permanently dormant in others. However, tiredness, stress, emotional events, hormone changes (such as menstruation), and even exposure to sun are risk factors that could lead to an outbreak. Unfortunately, it is impossible to get rid of the virus, but there are ways of curing an outbreak faster and, in some cases, reducing the frequency of outbreaks. Talk to your health professional about it!