What Are Cold Sores?

Cold sores are small painful blisters that form on or near the lips. Cold sores (or fever blisters) are very common. They usually go away on their own within 1 to 2 weeks.

What Are the Signs & Symptoms of Cold Sores?

Cold sores first form blisters on the lips, around the mouth, and sometimes inside the mouth. The blisters then become sores, which can make eating painful. They're filled with fluid, but crust over and form a scab before they go away.

Sometimes the virus causes redness and swelling of the gums, fever, muscle aches, a generally ill feeling, and swollen neck glands.

After someone first gets HSV-1, the virus can lie quietly in the body without causing any symptoms. But it can wake up again later from things like:

• other infections
• a fever
• sunlight
• cold weather
• menstrual periods
• stress, like before a big test at school

When the virus reactivates, it can cause tingling and numbness around the mouth before blisters appear.

What Causes Cold Sores?

The herpes simplex virus type 1 (HSV-1) causes cold sores. This is a different from herpes simplex virus type 2 (HSV-2). HSV-2 causes lesions in the genital area called genital herpes. Even though HSV-1 typically causes sores around the mouth and HSV-2 causes genital sores, these viruses can cause sores in either place.

How Do People Get Cold Sores?

People can get HSV-1 by kissing or touching someone with cold sores, or by sharing eating utensils, towels, or other items with an infected person. Many people with HSV-1 got it as kids during their preschool years.

How Are Cold Sores Treated?

Cold sores usually go away in about 1 to 2 weeks. No medicines can make the virus go away. But some treatments can help make cold sores less painful and not last as long:

• Cold compresses can help with discomfort.
• Prescription or over-the-counter treatments are sometimes recommended by the doctor.
• Cool foods and drinks can help make eating more comfortable.
• Taking acetaminophen or ibuprofen may ease pain. Don't take aspirin, as it's linked to a rare but serious illness called Reye syndrome.

When Should I Call the Doctor?

If you have a cold sore, it's important to see your doctor if:

• you have another health condition that has weakened your immune system
• the sores don't heal by themselves within 2 weeks
• you get cold sores often
• you have signs of a bacterial infection, such as fever, pus, or spreading redness

Can Cold Sores Be Prevented?

The virus that causes cold sores is very contagious. To help prevent it from spreading to others:

• Keep your drinking glasses and eating utensils, as well as washcloths and towels, separate from those used by other family members and wash these items well after use.
• Don't kiss others until the sores heal.
• Wash your hands well and often, especially after touching a cold sore.

Be especially careful not to touch your eyes. If HSV-1 gets into the eyes, it can cause a lot of damage.