Don't eat them. You might have oral allergy syndrome. This occurs when allergens in some raw fruits, vegetables & tree nuts resemble allergens in pollen - generally birch tree & ragweed. The resemblance and the consequent symptoms of itchy mouth & throat tickle disappear with sufficient heating of the food. Neither home nor medical cures work. See an allergist to help sort this out from true hazelnut allergy.
DON't eat them. Some allergists would categorize this as a form of anaphylaxis. If you continue to eat the filberts, you could have a life-threatening reaction. Tree nut allergies are among the more dangerous of food allergies. Not something to play with. Best to call your doctor asap about getting an allergy evaluation by an allergist.