Cold sores are caused by herpes simplex virus, or HSV-1. Up to 90 percent of adults in the United States have been exposed to HSV-1, according to the University of Maryland Medical Center in 2007. HSV-1 is transmitted through saliva. People who have weakened immune systems, such as those with HIV, and people undergoing cancer treatment are more likely to have severe cases. Once you have the virus, it can be reactivated by stress, sun exposure or illness.
First Outbreak Symptoms
According to Brown University Health Services, the first episodes of HSV-1 may be accompanied by a sore mouth, trouble eating, fever, swollen glands, tiredness and a general feeling of being sick. Because your body has no antibodies to the virus at the first exposure, symptoms tend to be more severe. Subsequent exposures may not involve feeling unwell, but they may last longer.
Prodromal Symptoms
The prodromal phase is the few days before blisters appear. Tingling, skin tightness, itching and burning around the mouth or nose may occur in the prodromal phase. A cold sore usually begins to develop 2 to 20 days after exposure, according to Brown University.
Blisters
Small fluid-filled blisters are the hallmark sign of an HSV-1 outbreak. A reddened area first appears on the skin, followed within a few hours by blisters. Small blisters may coalesce into larger blisters; the blisters are filled with yellow sticky fluid that forms crusts as the blisters rupture. Blisters may be painful or itchy. A herpes outbreak can take up to three weeks to resolve, according to the McKinley Health Center at the University of Illinois at Urbana-Champaign.
Blisters contain the virus and can spread it to other people. Touching your face and then touching something else without washing your hands can spread the virus. Touching another part of your body after touching your face can also spread the virus to that location. Some areas, such as the eyes and fingers, are more likely to develop herpes lesions. Good hand washing is essential to keep HSV-1 from spreading. Avoid kissing anyone until the blisters are gone. Mild over-the-counter antiseptics may help with the discomfort.
