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

Boy with a painful look on his face. Could it be Coldsores?

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.

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 is cold sores?

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 cold sores?

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 of cold sores?

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.

Is cold sores contagious?

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

How long does cold sores 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 is cold sores 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 is cold sores 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 cold sores 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.

Related concepts:

Fever Blisters, Herpes Labialis, Secondary Herpes.

Dr. Alan Greene

Dr. Greene is the founder of (cited by the AMA as “the pioneer physician Web site”), a practicing pediatrician, father of four, & author of Raising Baby Green & Feeding Baby Green. He appears frequently in the media including such venues as the The New York Times, the TODAY Show, Good Morning America, & the Dr. Oz Show.