Cold Sore

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Cold sores — also called fever blisters — are tiny, fluid-filled lesions that occur on and around your lips. These blisters are often grouped together in patches.

Cold sores spread from person to person by close personal contacts, such as kissing or sharing eating utensils, razors, and towels. The sores are caused by herpes simplex virus type 1 (HSV-1) that’s closely related to the type that causes genital herpes (HSV-2). Oral sex can spread HSV-1 to the genitals and HSV-2 to the lips.


A cold sore usually passes through several stages, which include:

  • Tingling and itching. Many people feel an itching, burning, or tingling sensation around their lips for a day or two before cold sore blisters erupt.
  • Blisters. Small fluid-filled blisters typically break out along the border where the outside edge of the lips meets the skin of the face. Blisters can also occur around the nose or on the cheeks. Children younger than age 5 may have cold sores inside their mouths that are mistaken for canker sores.
  • Oozing and crusting. The small blisters may merge and then burst, leaving shallow open sores that will ooze fluid and then crust over.


A cold sore generally clears up without treatment within about two weeks. Sometimes medications to speed the healing process may be prescribed.

If you develop cold sores frequently or if you’re at high risk of serious complications, your doctor may prescribe an antiviral medication that you take on a regular basis.

An over-the-counter cream may be used to treat cold sores. It must be applied frequently and may shorten an outbreak by a few hours or a day.

      Excerpt From: The Mayo Clinic. “Mayo Clinic A to Z Health Guide”.

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