Aphthous Ulcers Shiny Why Does My Son Keep Getting Canker Sores (aphthous Ulcers)?

Why does my son keep getting canker sores (aphthous ulcers)? - aphthous ulcers shiny

My son is 9 years old and had to break for years cancer wounds, I had (the doctor said it was nothing) that the dentist has seen and has no answer and continues to enjoy her. At first I thought maybe it was his toothpaste and tried all the different species, but outbreaks remains. It is 4.6 cancers and both are so painful that you are looking for are very important and has a hard time eating. I am sorry for the Wee-Man, but you do not know how to stop. We have all the treatments to cure them, but do not want it I want to be going on and would not return. Suggestions on what it can lead to
Thanks
Mom