Cold Sores (Fever Blisters)

What are cold sores?

Cold sores are a cluster of painful 1 to 3 millimeter bumps or blisters on the outer lip. They happen only on one side of the mouth. Just before a cold sore develops, your child may feel a tingling or burning on the outer lip at the same place where he had cold sores before.

What is the cause?

Cold sores are caused by the herpes simplex virus. The sores happen for the first time after your child has had contact with someone with herpes. Thereafter, the virus lives in the sensory nerve and can cause cold sores again. About 2% of people have recurring cold sores. The sores come back because of sunburn, fever, friction, or physical exhaustion.

How long do they last?

The blisters will rupture, scab over, and dry up. The whole process takes 10 to 14 days. The sores do not cause scars. Treatment can shorten the course by many days.

How can I take care of my child?

• Antiviral ointment

  Once you get fever blisters, you usually can't shorten the time that you have them unless you start applying an antiherpes ointment as soon as any small bumps appear. These ointments require a prescription. If you don't have an antiherpes ointment, cover the fever blisters with petroleum jelly to reduce the pain and to promote healing.

  Your child's ointment is __________________________. Apply it _______ times a day for _______ days. The ointment can reduce the severity of the sores only if treatment is started early.

How can cold sores be prevented?

Since fever blisters are often triggered by exposure to intense sunlight, prevent them in the future by using a lip balm containing sunscreen. If blisters are not yet present, apply an ice cube or ice pack to the tingly area continuously for 90 minutes. This will sometimes stop the infection.

Avoid spreading this germ to another person's eye because an infection there can be serious. Therefore, discourage picking, and wash the hands frequently. Since the condition is contagious, have your child avoid kissing other people during this time. If your child is young and puts everything in his mouth, avoid sharing toys with other kids for a week.

If your teenager is going skiing or to the beach and has had frequent herpes flareups in the past, despite careful use of sunscreen, call your physician. Recent research has found that starting oral antiherpes medication (pills) before such outings can prevent most flareups.

When should I call my child's health care provider?

Call during office hours if:

• Any sores occur near the eye.
• The sores last longer than 2 weeks.
• You have questions about antiherpes ointments.
• You have other concerns or questions.