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.