What is cold sores?

Cold Sores

Cold sores in children: Overview

Cold sores are clusters of small blisters on the lip and skin around or inside the mouth. Often the first sign of a cold sore is a spot that tingles, burns, or itches. A blister usually forms within 24 hours. The skin around the blisters can be red and inflamed. The blisters can break open, weep a clear fluid, and then scab over after a few days. Cold sores most often heal in 7 to 10 days without a scar. They are sometimes called fever blisters.

Cold sores are caused by a virus called the herpes simplex virus.

Cold sores most often go away on their own. But if they are severe or cause pain, your doctor may prescribe antiviral medicine to relieve pain and help prevent outbreaks.

Cold sores

Cold sores, sometimes called fever blisters, are groups of small blisters on the lip and around the mouth. The skin around the blisters is often red, swollen, and sore. The blisters may break open, leak a clear fluid, and then scab over after a few days. They usually heal in 7 to 10 days.

Cold sores are most contagious until the blisters are completely healed.

What are the symptoms of cold sores?

The first symptoms of cold sores may include a spot that tingles, burns, or itches around your mouth and on your lips. A blister usually forms within 24 hours.

You may also have a sore mouth, a fever, a sore throat, or swollen glands in your neck or other parts of the body. Small children sometimes drool before cold sores appear.

After the blisters appear, the cold sores usually break open, leak a clear fluid, and then crust over. They usually heal in 7 to 10 days. For some people, cold sores can be very painful.

Some people have the virus but don't get cold sores. They have no symptoms.

You may not get cold sores when you are first infected with the herpes simplex virus (HSV). If cold sores do form when you are first infected, they may be more severe than in later outbreaks.

How are cold sores treated?

Cold sores usually start to heal on their own in 7 to 10 days. Treatment can get rid of cold sores faster, and it can also help ease painful blisters or other symptoms.

Treatment may include:

  • Oral antiviral medicines. These can reduce pain and slightly improve healing time.
  • Topical creams or ointments. They may reduce pain, itching, and healing time.

To prevent recurring cold sores, oral antivirals may also be taken daily. This can be especially helpful for people who have frequent and painful outbreaks.

There is no cure for cold sores or the virus that causes them.

How can you prevent cold sores?

There are some things you can do to keep from getting the virus that causes cold sores. For example, avoid kissing a person who has cold sores. Don't share cups, utensils, or other items that a person with cold sores may have used.

How are cold sores diagnosed?

Your doctor can tell if you have cold sores by looking at the sore and asking you questions to find out if you have come into contact with the herpes simplex virus. You probably won't need any tests.

If it's not clear that you have cold sores, herpes tests may be done. The doctor takes a sample of fluid from a sore and has it tested. Having the sample taken usually isn't uncomfortable even if the sore is tender or painful.

How can you care for a child who has cold sores?

  • Tell your child to wash their hands a lot. Tell them to try not to touch the cold sore. This will help to avoid spreading the virus. The virus is more likely to spread if this is your child's first cold sore outbreak.
  • Keep your child's towels and other objects away from other members of your family while your child has a cold sore.
  • Try placing a cold, wet towel on the sore. This may help to relieve pain and reduce swelling.
  • If your child's doctor prescribed antiviral medicine to relieve pain and help prevent outbreaks, be sure to follow the directions.
  • Give your child acetaminophen (Tylenol) or ibuprofen (Advil, Motrin) for pain. Read and follow all instructions on the label. Do not give aspirin to anyone younger than 20. It has been linked to Reye syndrome, a serious illness.
  • Do not give your child two or more pain medicines at the same time unless the doctor told you to. Many pain medicines have acetaminophen, which is Tylenol. Too much acetaminophen (Tylenol) can be harmful.
  • Avoid citrus fruit, tomatoes, and other foods that contain acid.
  • Remind your child not to share utensils or kiss anyone while they have a cold sore.

To prevent cold sores in the future

  • Try to get your child to wear a hat to protect their lips from the sun.
  • Using lip balm that contains sunscreen on your child's lips may help reduce outbreaks of cold sores.

What puts you at risk of getting cold sores?

Being exposed to the herpes simplex virus (HSV) can put you at risk of getting cold sores. But many people have the virus and may never get cold sores. People who have weakened immune systems are at higher risk of having more severe and longer-lasting outbreaks of cold sores.

How do cold sores spread?

The herpes simplex virus that causes cold sores usually enters the body through a break in the skin around or inside the mouth. It's usually spread when a person touches a cold sore or touches infected fluid. This can happen when you share eating utensils or razors, kiss an infected person, or touch that person's saliva. A parent who has a cold sore often spreads the infection to their child in this way.

A person can spread the virus to someone else a few days before the sore appears. The person is most contagious until the sore is completely healed.

How is complementary medicine used to treat cold sores?

Several complementary treatments may help provide relief during a cold sore outbreak. They include:

  • Vitamin C.
  • Lysine supplements.
  • Lemon balm.

Vitamin C may be taken by mouth as a tablet. Or you can use it in a cream that you put on the cold sore (topical cream). Or you can apply liquid vitamin C onto the cold sore. Lysine supplements are taken as pills. Lemon balm is available in a topical cream.

Zinc oxide topical cream may reduce how long an outbreak lasts.

What are cold sores?

Cold sores, sometimes called fever blisters, are groups of small blisters on the lip and around the mouth. The skin around the blisters is often red, swollen, and sore. They usually heal in 7 to 10 days. Cold sores are most contagious until the blisters are completely healed.

Herpes simplex virus type 1 symptoms (cold sores)

Location of cold sores near mouth, with close-up of blisters

Herpes simplex virus type 1 (HSV-1) can cause groups of small blisters that usually appear on the lip and around or inside the mouth. The groups of blisters are commonly called cold sores. They may be itchy or painful.

Cold sores in children: When to call

Call your doctor now or seek immediate medical care if:

  • Your child's cold sores are painful and you want to try antiviral medicine.
  • Your child has signs of infection, such as:
    • Increased pain, swelling, warmth, or redness.
    • Red streaks leading from a cold sore.
    • Pus draining from a cold sore.
    • A fever.
  • Your child has a cold sore and develops eye pain, eye discharge, or any vision changes.

Watch closely for changes in your child's health, and be sure to contact your doctor if:

  • The cold sore does not heal in 7 to 10 days.
  • Your child gets cold sores often.

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The content above contains general health information provided by Healthwise, Incorporated, and reviewed by its medical experts. This content should not replace the advice of your healthcare provider. Not all treatments or services described are offered as services by us. For recommended treatments, please consult your healthcare provider.

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