Canker sores (aphthous stomatitis)
Canker sores, or aphthous stomatitis, is an illness that causes small ulcers to appear in the mouth, usually inside the lips, on the cheeks or on the tongue.
Canker sores are usually seen in children and adolescents from the ages of 10 to 19 years. For about one-third of the children affected, lesions continue to reappear for years after the initial outbreak.
If your child has canker sores, it's important to know that they aren't contagious and can't be spread from one child to another.