heather lives in constant danger ofoo tt n keerer sick. >> i'm allergic to peanuts, tree ts, and shlfish, and found out when i went to an ice-cream storwh iaseay un i tulyicd t es toppings that were peanut-butter cookies, and i had a full reacon. >> and she just started crying d kn setngast right, but i really was confused and unre whait was. it can ta many trips to a onanju wt odarto out what's blame, but the underlying cause is a problem witthe body's immune system. ott fm feio, ke works to bacteria or viruses or parasites, but sometimes, it gets confused, and it starts recoizg foodasn enem and it starts mounting an immune response. >> that response can range from hives, vomiting, even difficulty breathing. very severe symptoms are called anaphylaxis. anhyxiis not onlscary -- it can be deadly, and it can happen in an instant. >> your throat closes. his l eroubo. your eyes puff up. it's different for everybody, ally, but it gets really fatal. [ siren wails ] ery 10 minutes, someone in the u.s. is rushed to the emergency room with a severe allergic reaction. e congorcoon.food allergies p