An allergen is a chemical in food that causes the allergic reaction. Food allergies an be deadly, as with a peanut allergy, which can kill you dead, or mild, as with my father-in-law who would get dry eyes after eating a banana.
It’s a mistake to think that allergens can be destroyed by cooking, even at high heat such as deep frying or grilling. For example, French fries may see fine for someone with a peanut allergy, but not if they are fried in peanut oil. It’s true that cooking works sometime. For example, people with dairy allergies may be able to eat cooked items, such as a cake, that contain milk. So don’t count on cooking to save the day!