Cold sores are small and painful blisters that can appear around the mouth, face, or nose. Sometimes referred to as fever blisters, they're caused by herpes simplex virus type 1 (HSV-1). Kids can get cold sores by kissing or sharing eating utensils with an infected person.
Colds sores in the mouth are very common, and many kids get infected with HSV-1 during the preschool years. The sores usually go away on their own within about a week.
Most kids who get cold sores get infected by eating or drinking from the same utensils as someone who is infected with the herpes virus or by getting kissed by an infected adult.
The cold sores first form blisters on the lips and inside the mouth. The blisters then become sores. In some cases, the gums become red and swollen. In other cases, the virus also leads to a fever, muscle aches, eating difficulties, a generally ill feeling, irritability, and swollen neck glands. These symptoms can last up to 2 weeks.
After a child is initially infected, the virus can lie dormant without causing any symptoms. But it can reactivate later, typically after some sort of stress like other infections, fever, sunlight, cold weather, menstrual periods, or even before a big test at school. When the virus is reactivated, it can cause tingling and numbness around the mouth before blisters appear.
Usually, HSV-1 causes cold sores in the mouth or face, and herpes simplex virus type 2 (HSV-2) causes lesions in the genital area, resulting in genital herpes. But sometimes, HSV-1 can cause genital lesions as well, especially if someone has received oral sex from an infected partner.
Cold sores from HSV-1 usually go away in about a week. Although no medications can make the infection go away, some treatments are available that can shorten the length of the outbreak and make the cold sores less painful.
Cool foods and drinks can help relieve discomfort, and acetaminophen may also ease the pain. Aspirin should not be given to kids with viral infections since it has been associated with Reye syndrome.
Call the doctor if your child:
has another health condition that has weakened the immune system, which could allow the HSV infection to spread and cause problems in other parts of the body
has sores that don't heal by themselves within 7 to 10 days
has any sores near the eyes
gets cold sores frequently
Since the virus that causes cold sores is so contagious, it's important to prevent it from spreading to other family members. Precautions to take with kids who have cold sores include:
keeping their drinking glasses and eating utensils, as well as washcloths and towels, separate from those used by other family members and washing these items thoroughly after use
teaching them not to kiss others until the sores heal
having them wash their hands frequently and as soon as possible after touching the cold sores
trying to keep them from touching their eyes — if HSV infects the eyes, it can be very serious
If you're caring for a child with a cold sore, you also should be sure to wash your hands frequently so that you don't contract the virus or spread it to others.