There are many different types of allergens: dust, pollen, pets, insect stings, peanuts, soy, and penicillin. Some people get hives and itch from cold weather. Others get a rash and blisters from the metal in jewelry, coins, or keys.
Sometimes all kids have to do is stay away from what makes them wheeze or itch. If they can't avoid allergens, mild symptoms can usually be treated with over-the-counter medicines.
People with serious reactions may have to carry emergency kits or wear bracelets that explain their allergies.