What Are Fever Blisters?

Fever blister, also known as cold sores are a nuisance that causes annoyance and discomfort to millions of Americans.  The condition is caused by a contagious herpes virus, either herpes simplex one or herpes simplex 2.  Over 95% of cases are caused by herpes simplex virus one (HSV1).  The virus causes “blisters” or small sores that are found on the face, lips, or in the mouth or in the nostrils.  These sores cause pain, itching, and burning before crusting over.

Most people who carry the infection become infected with the virus before the age of ten.  The virus invades the membrane cells of the lips, nose or mouth.  For most people, the initial infection does not cause any initial symptoms.  However, about 15% of individuals develop fluid-filled blisters inside and around the mouth 3-5 days after contracting the virus.  These symptoms may be accompanied by fever, body aches, and swollen glands.  The blisters usually crust over and heal within 2-3 weeks.

Although the sores heal, the herpes virus remains in the body.  The virus lies dormant in nerve cells in the skin.  The virus may remain inactive or it may travel to the surface of the skin and cause another outbreak.  Reoccurrence may be caused by viral infections or fever, stress, fatigue, exposure to sunlight or wind, hormonal changes (like menstruation) and changes to the immune system.

The herpes virus is highly contagious when blisters are present and is passed from person to person by close contact such as kissing.  Children often become infected from close contact with parents or siblings who have the virus.  The virus is contagious even if the cold sores are not present.

There is no cure for herpes simplex virus, but antiviral medications may shorten the length of the illness, help the sores heal and reduce the number of occurrences.  An individual who has an outbreak should avoid touching the sores to prevent spreading the sore to other areas such as the eyes.  To avoid infecting others, don’t touch the sores then touch others and refrain from kissing other individuals.