Allergies are really weird! If he's been with you two years than he's at least 2 years old and NOT too young to be tested. My daughter was tested for peanut allergy at 19 months. I also have daycare boy who is allergic to many things. I told his mom he needed to be tested and come back with an Epipen when he was 1.

If they are concerned they need to get him tested....not just imply that something you gave him caused a reaction.