What Are Cold Sores?

Cold sores, also known as fever blisters, are tiny, clear, fluid-filled blisters that form around the mouth and are caused by the herpes simplex virus (usually type 1, or HSV-1) living inside your nerve tissue. Cold sores usually do not last longer than two weeks. However, the sores are highly contagious and tend to recur when the virus is reactivated by a trigger such as stress, sunlight, fever or illness.

Cold Sore Vs. Canker Sore

Like cold sores, canker sores (also known as aphthous ulcers) can be quite painful and often recur. While cold sores are caused by a virus, the formation of a canker sore may be triggered by multiple factors such as stress, food allergies or a weakened immune system. A canker sore forms in the soft tissues of your mouth and is not contagious, whereas a cold sore usually appears around the lip area outside the mouth and is highly contagious. If a cold sore appears inside the mouth, usually it appears on the non-movable parts such as the roof, rather than the tongue or soft palate.

How Are Cold Sores Treated?

Most cold sores are mild and do not require treatment. Antiviral medications can reduce the frequency, duration and severity of outbreaks. Medications with a numbing agent, such as benzyl alcohol, can help alleviate a cold sore’s burning, itching and pain. Emollients can reduce cracking and soften scabs. Applying aloe vera balm three times a day to the cold sore also can help fight the infection and enhance healing.

If over-the-counter remedies don’t help, ask your dentist for a prescription. A dentist also can accurately diagnose cold sores and base treatment on important factors such as your age, overall health, medical history and tolerance for specific medications.

How to Minimize Outbreaks

To prevent transmission of the virus to another person, avoid:

  • Intimate physical contact with others
  • Sharing eating utensils, toothbrushes, towels and razors
  • Touching the blisters (always wash your hands after applying medication)

How to minimize recurrent outbreaks:

  • Eat foods high in lysine (an amino acid found in red meats, fish and dairy products) or take supplements
  • Apply sunscreen to the face and lips before going outdoors
  • Shave with a disposable razor during an outbreak
  • Replace your toothbrush
  • Engage in relaxing activities to reduce stress