What Is a Cold Sore?


Quick Answer

A cold sore is a very small blister that is filled with fluid and is caused by a viral infection, according to Mayo Clinic. It is also known as a fever blister. Cold sores are known to appear in groups, and it is common for a crust to form over the blisters after they are broken.

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Full Answer

Cold sores are caused by a herpes simplex virus called HSV-1 that is similar to the virus that causes genital herpes, HSV-2, notes Mayo Clinic. Even if the sores are not visible, cold sores can be spread, and they can affect the mouth or the genitals. Although there is no cure for cold sores as of 2015, antiviral medications can be used to keep them at bay and increase healing time.

It is common for cold sores to go through multiple stages, states Mayo Clinic. The first symptom is tingling and itching, and then blisters usually appear near the boundary of the lips and skin, followed by oozing and crusting. During the first outbreak of HSV-1, a person may experience other symptoms, including fever, sore throat, headache and sore muscles. The first may outbreak may also cause swollen lymph nodes or painful eroded gums.

Experts recommend seeing a doctor if cold sores cause a weakened immune system or if they do not clear up within two weeks, recommends Mayo Clinic. If sores return frequently, become severe, or if eye irritation occurs, it is important to seek medical assistance.

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