E.B.
Please just don't "go Paleo".
Does your son have symptoms, such as vomiting, nausea, skin conditions, digestive problems, pain, constipation, fatigue, headaches, sleep disturbances or any of the many problems that can be caused by allergies? Are you concerned about his physical well-being? Is he sick often?
How were your son's allergies diagnosed? Did he have biopsies, skin prick testing, blood tests?
Did a medical professional diagnose him or was he determined to have allergies by a chiropractor or a person who sells supplements?
Does he have celiac disease (diagnosed by scopes, biopsies and blood tests)?
Did the professional use the words sensitivity or allergy? Or was this a suggestion, to try eliminating certain foods to see if certain symptoms might improve?
If your son has medical conditions or symptoms, then, if you haven't already, please have him professionally evaluated by a medical doctor (an allergist or gastroenterologist or internist) and then ask him or her for an explanation of your son's condition. Is it a true allergy, or a sensitivity? Take notes.
Then see a nutritionist or dietician whom the doctor recommends. If your son is old enough to read and discuss this, get him involved with the nutritionist.
If these "allergies" are a recommendation by someone who does acupuncture or who sells supplements or who is a life coach or someone who has "read" your son by looking at him or feeling his wrists or listening to him breathe,or someone whose child had allergies and is "sure" your son has the same problems, then walk away and if you feel your son has medical problems, get to an internist or allergist.
Don't just google Paleo and change everything without a nutritionist's advice (that's fine if you just feel like eating according to the Paleo plan and don't have a growing child to consider, but if someone has medical needs, a medical specialist needs to be involved). A doctor will make sure that his or her patient will have proper follow-up care and the right resources.
My daughter is truly allergic to some unusual foods (diagnosed by blood tests and skin tests and biopsies and other tests) and after seeing the allergist and the GI specialist and the internist, and seeing the hospital dietary/nutrition counselor, we all got great information and education. We learned how to make sure she was getting the nutrition she needed, how to read menus, how to read labels, how to advocate for her (what to do when people say "oh nobody's allergic to that, it's a great health food", but yes - she is truly and medically allergic to it!), how she can advocate for herself, and how to make intelligent substitutes.