Causes

• Canker Sores: The main cause of 1 or 2 ulcers after age 5
• Hand-foot-mouth disease: The most common cause of multiple ulcers in the mouth, mainly on the tongue and sides of the mouth. It is common between ages 1 to 5 years.
• Herpes Virus (Cold sore virus): The first infection can be severe and cause 10 or more ulcers on the gums, tongue and lips. Also, fever and difficulty swallowing. Usually occurs age 1 to 3.