Urticaria is a relatively simple condition with the same or similar clinical manifestations, but the causes are very different. Two people suffer from urticaria but the causes are different; even if the same person relapses at different times, for example, six months after urticaria has been cured, the causes may not be the same before and after. So the causes of hives are very complex, the common ones are as follows: 1. Food: Human beings have a variety of recipes, of which animal foods such as fish, shrimp, crab, milk, eggs, etc. are the most common, especially not fresh or spoiled seafood, meat is most likely to cause hives. Plant foods such as mangoes, pineapples, strawberries, tomatoes and cocoa, including garlic, mustard and other condiments, can also cause the onset of the disease. Food-induced urticaria is often accompanied by gastrointestinal symptoms such as nausea, vomiting and abdominal pain in addition to the rash. 2. Inhalants: Inhalation of certain pollen, dust, house dust, animal dander, down, fungal spores and the smell of newly renovated rooms can occasionally cause urticaria and is often accompanied by respiratory symptoms such as nasal congestion, runny nose and sore throat. 3. Drugs: ① Certain anti-inflammatory drugs such as penicillin, cephalosporins, sulfonamides, dysentery, etc. 4, infection: including bacteria, viruses, fungi, parasites, etc. may cause urticaria; it may be inflammation of the skin and the five senses, such as The hives may be caused by inflammation of the skin and the five senses, such as folliculitis, impetigo, sinusitis, otitis media, tonsillitis, or chronic inflammation of internal organs, such as hepatitis B, gastritis and certain gynecological inflammations. 5, insects: often occurring in summer and autumn, related to the bites of lice, fleas, wasps, bees, caterpillars, etc. 6, physical factors: many hives are related to hot and cold stimulation, sunlight exposure, mechanical friction, pressure, etc. 7, mental factors: long-term excessive tension The most common cause of urticaria is the presence of a large number of people in the body, such as the elderly, the elderly, and the elderly. 8, visceral and systemic diseases: such as rheumatic fever, rheumatoid arthritis, lupus erythematosus, malignant tumors, aspergillosis, dermatomyositis, herpes-like dermatitis, menstrual disorders, pregnancy, etc. sometimes also become the cause of urticaria. 9, endocrine disorders, metabolic disorders, gastrointestinal dysfunction, etc. also tend to induce chronic urticaria.