(HealthDay News) -- Cold sores are painful red or purple blisters that usually form on the lips or around the mouth. Caused by the herpes simplex virus, cold sores can spread to other parts of the body or to other people.
Certain factors may make children more susceptible to cold sores, says the Nemours Foundation -- including stress or too much exposure to the sun. If your child's immune system is weakened by another condition or illness, it may also make him more likely to contract cold sores.
You can help prevent cold sores by making sure your child eats a healthy, balanced diet and gets enough sleep. If your child has a tendency to get cold sores, applying sunblock or lip balm on the mouth before he goes outdoors may help reduce his chances of an outbreak.
