Clinical symptoms of urticaria are mainly manifested as wheals and angioedema. Wheals are central, edematous masses confined and elevated on the surface of the skin and mucous membranes, which are caused by the dilatation of small blood vessels in the skin and mucous membranes due to the weakness of the mast cells, as well as an increase in permeability. It is often surrounded by a reductive erythema, which usually disappears within 24 h. The large rash may recur. Angioedema presents as a sudden red color, swelling and pain involving the deep dermis as well as subcutaneous tissues and mucous membranes, rather than itching. Angioedema is slow to resolve and healing is relatively good in the vast majority of patients, except for a small number of patients with complications in the respiratory tract or other systems. Urticaria can occur at any age, and it is currently believed that urticaria is treated by removing the cause, finding the allergens, and treating aggressively in order to eliminate the symptoms more completely.