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Dental & Mouth Conditions
Cold Sores
July 20, 2026

Cold sores appear on or near the lips. They are painful and unpleasant. Over 50% of people will have them. Cold sores are also called fever blisters.
Signs & Symptoms
- Tingling feeling on or near the lips for 36 to 48 hours before the sore appears
- Itching at the site (early sign)
- Small, red blisters with pus-filled centers
- Blisters form a yellow crust that lasts about 10 days
- One sore or a cluster of sores
Causes, Risk Factors & Care
Cold sores are caused by the herpes simplex virus (HSV), either HSV-1 (this is most often the cause) or HSV-2 (the usual cause of genital herpes). The virus lies dormant in the body and can return. A fever, cold, stress, cold or windy weather, and strong sun exposure are triggers for outbreaks.
Cold sores are very contagious, especially when the blisters rupture and weep.
Cold sores are treated with self-care and antiviral medications, such as acyclovir and penciclovir. Prompt treatment may reduce the discomfort.
Prevention
To avoid getting or spreading cold sores:
- Don’t share drinking glasses, towels, or cooking utensils.
- Don’t touch cold sores with your fingers. If you do touch the cold sores, do not touch your eyes. This could cause a serious eye infection.
- Wash your hands often.
- Avoid kissing or direct skin contact with the sores. This includes oral sex. The virus that causes cold sores can cause genital herpes, too.
- When in the sun, wear a hat and use a sunblock with a sun-protective factor (SPF) of 30 or more on the lips.
- Use a lip balm on cold or windy days.
- Ask your doctor about a prescribed antiviral medicine to take or apply when you feel a cold sore coming on.
- Try to figure out what triggers the sores. Once you identify a trigger, do what you can to avoid it.
Self-Care
- Keep the sore clean and dry.
- Apply antiviral medication, if prescribed, to the affected area at the first sign of a cold sore.
- Try an over-the-counter treatment, such as Abreva antiviral cream, Campho-Phenique, Blistex, or make a paste with cornstarch and water. Dab some on the sore with a cotton swab.
- Dab aloe vera or petroleum jelly on the sore. Use a cotton swab.