The exact cause of allergy is not yet known, and some patients have too low immunity. Allergy is a special kind of constitution formed on the basis of genetic predisposition, and people with this constitution are prone to allergic reactions when they come into contact with sensitizers such as seafood, pollen, dust, chemical agents and fragrances. The specific cause of the formation of this constitution has not yet been studied clearly, some patients with improper diet or stress caused by low immunity is related. Allergy sufferers should try to stay away from allergens in normal times, and insist on regular physical exercise, which is effective in strengthening the body’s resistance and improving the allergic body. Due to the severe allergy, easy to appear laryngeal edema, asphyxia, coma or death and other serious consequences, so once an allergic reaction, should go to the regular hospital in time for diagnosis and treatment.