The pathogenesis of urticaria is caused by various factors that lead to temporary inflammatory congestion of the mucosal vessels of the skin and massive fluid exudation, resulting in localized edematous damage that occurs and subsides rapidly, with severe itching. There may be fever, abdominal pain, diarrhea or other systemic symptoms. Urticaria is a condition in which red patches of varying shapes and sizes appear on unspecified areas of the body when exposed to allergens or when disease-causing agents are present in the body. These patches may be itchy in the areas where they occur. If exposure to the allergen is not stopped and treated, the itchy rash will increase. The common causes of hives are: (1) Food. Fish, shrimp, crab, and eggs are the most common, and certain spices and condiments can also cause it. (2) Drugs. Such as penicillin, sulfonamides, dysentery, serum vaccines, etc., often through the immune mechanism to trigger urticaria; and aspirin, morphine, atropine, vitamin B1 and other drugs for histamine release, can directly cause the release of histamine mast cells to trigger urticaria. (3) Infection. Including viruses (e.g. hepatitis virus), bacteria (e.g. Staphylococcus aureus), fungi and parasites (e.g. roundworms). (4) Animal and plant factors. Such as insect bites or inhalation of pollen, feathers, dander, etc. (5) Physical factors. Such as heat and cold, sunlight, friction and pressure can be caused. In addition, gastrointestinal diseases, metabolic disorders, endocrine disorders and mental factors can also cause. Antihistamines can be treated There are many irritants in the body that can cause urticaria, and we can collectively refer to these irritants as mediators, of which histamine is the most important mediator that causes this disease. Antihistamines are important drugs in the treatment of various types of urticaria and can control the symptoms in most patients. Although antihistamines do not directly counteract or neutralize histamine and cannot prevent its release, they have a scrambling effect on histamine and can rapidly inhibit the production of wind clumps. Levocetirizine is a new generation of highly effective non-sedating antihistamine, which is the R-isomer of cetirizine and has twice the affinity for H1 receptors than cetirizine. Studies have shown that levocetirizine hydrochloride has not only antagonistic effects on histamine, but also inhibits the release of histamine and various inflammatory transmitters associated with metabolic reactions. For chronic idiopathic urticaria, levocetirizine hydrochloride has the advantages of rapid onset of action, long duration of action, good tolerability, and good clinical safety. Adverse reactions are mild and mostly self-resolving. Common adverse reactions include drowsiness, dry mouth, headache, and fatigue. Precautions: Use with caution if you have a history of liver dysfunction or impairment; use with caution during overhead work, driving or operating machinery; avoid taking with sedatives; avoid using this product after drinking; reduce the dosage of this product in patients with impaired renal function; contraindicated in pregnant and lactating women; the safety of the drug in children under two weeks of age has not been determined; it should also be used with caution in the elderly because of physiological decline. Depending on the type and extent of urticaria, levocetirizine, pansentin and cimetidine are also used in combination with levocetirizine hydrochloride and cyproheptadine to treat chronic urticaria, or levocetirizine hydrochloride and cyproheptadine in combination with BCG polysaccharide nucleic acid to treat chronic urticaria, or levocetirizine hydrochloride and ranitidine in combination to treat chronic urticaria. It can also be combined with a combination of topical creams containing antibiotics and steroids, or with herbal water scrubs and other combination regimens. Patients must take special care while taking the medication: follow the doctor’s prescription and dosage exactly. After a period of continuous medication, the doctor will slowly reduce the dosage according to the patient’s condition (perhaps from daily to every other day) until the medication is completely cured. The medication should be administered for at least 1 month during the acute phase. Do not stop taking the medication or reduce the dose during the medication period to avoid losing the previous work. The patient should also pay attention in daily life: do not scratch with your hands, this action not only can not stop the itch, but also may scratch more and more itch; do not apply heat, heat will make the blood vessels tense, releasing more allergens; avoid eating artificial additives and fried, spicy food; eat more fresh fruits and vegetables rich in vitamins, eat more alkaline food, such as grapes, kelp, tomatoes, sesame, cucumber, carrots, bananas , mung beans, barley, etc.