Urticaria is an allergic disease, the causes of its onset are diverse, common allergens are: 1, nature through the respiratory tract inhalation, such as pollen, dust mites, kept dogs and cats fur, room in the humid appearance of mold. 2, is to eat food, such as fish and shrimp seafood, beef and mutton, milk, eggs, a variety of fruits. 3, drugs, commonly used penicillins, cephalosporins, sulfonamides, etc. are common causes of hives. 4, other causes, such as viral or bacterial infections may also lead to the occurrence of hives; some systemic diseases and natural warming factors, stress, etc. may also lead to the appearance of hives.