Cold Sores: A-to-Z Guide from Diagnosis to Treatment to Prevention

Cold sores can affect anyone who has had a prior herpes infection (up to a third of children have by the time they grow up).

Introduction to cold sores:

Kids often feel the tingling before you can see the sore. If your child has a cold sore, he is likely to have them again and again before he grows up. You will want to learn what to expect and what to do when cold sores re-emerge.

A cold sore does not mean that your child has recently been exposed to herpes. People don’t get cold sores with the first herpes infection.

What are they?

Cold sores or fever blisters are caused when a prior herpes infection flares up again. They are usually caused by herpes simplex type 1 (HSV-1).

Who gets them?

Cold sores can affect anyone who has had a prior herpes infection (up to a third of children have by the time they grow up). They are most likely to occur during times of change or stress, including sunburns, fatigue, illnesses, allergies, fevers, temperature changes, or along with the menstrual cycle.

What are the symptoms?

Children usually have one or several blisters on or around the mouth – most often at the border of the lip and the skin of the face. They occasionally occur elsewhere (such as the palate).

The blisters or ulcers are often accompanied or preceded by tingling or itching.

Are they contagious?

Cold sores are quite contagious, either by direct contact or by contact with mouth secretions.

How long do they last?

Once infected, people have the herpes virus for life. Individual cold sores tend to last for about 3 to 7 days. They are most contagious during the first three or four days.

How are they diagnosed?

Cold sores are often diagnosed based on the symptoms and physical exam. The diagnosis can be confirmed with a variety of viral tests.

How are they treated?

Prescription antiviral medications are available, but the benefit they confer may not outweigh the costs for many kids. If used, they are best started at the very beginning of a cold sore — within the first 24 hours. If cold sores are frequent and problematic, you might want to have the medicine on hand.

Sleep and lots of non-acidic liquids to drink can help. Options for pain relief include acetaminophen, ibuprofen, or a variety of ointments or mouth rinses your pediatrician can recommend.

Do not use steroid creams or gels on a suspected herpes infection – this could make the infection worse.

How can they be prevented?

Avoiding close contact with people shedding the virus is the best way to avoid primary herpes (see article on herpes simplex). Teach your child not to share drinks or utensils, and not to exchange kisses with someone with mouth sores.

Once infected, cold sores are best reduced by maintaining good sleep, good nutrition, and good health in general. Sometimes cold sores are unavoidable.

Fever Blisters, Herpes Labialis, Secondary Herpes.

Last medical review on: August 21, 2013
About the Author
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Dr. Greene is a practicing physician, author, national and international TEDx speaker, and global health advocate. He is a graduate of Princeton University and University of California San Francisco.
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