The rash of this disease is similar to the skin damage caused by a person exposed to plant nettles, so it is called urticaria. The rash is a windy, flushed patch, varying in size and duration of attack, and varying in shape, with the clusters gradually spreading and fusing into patches. The clusters last from a few minutes to a few hours, and a few can last up to several days before fading away without leaving a trace. The rash often occurs suddenly and in batches, with most of them occurring in the evening. The rash may be generalized or limited, and sometimes combined with angioedema. Sometimes the rash is ring-shaped, called ring urticaria, and several adjacent ring-shaped lesions can fuse with each other to form a map, called map urticaria. Sometimes, there are petechiae in the center of the damage, called hemorrhagic urticaria, and the kidneys and stomach and intestines can bleed at the same time. When there are blisters in the rubella mass, it is called blistering urticaria. When there are large blisters, it is called urticaria herpetiformis. Acute urticaria is often acute, with sudden itching of the skin, soon appearing in varying sizes, in large numbers, and more widely, often combined with systemic symptoms. If the mucous membrane of the lips is involved, it causes acute laryngeal edema and respiratory distress, or suffocation in severe cases; if the mucous membrane of the gastrointestinal tract is involved, abdominal pain and diarrhea may occur. In severe cases, symptoms of anaphylaxis such as panic, irritability, nausea, vomiting, and lowered blood pressure are often associated with the disease. The duration of the disease is usually 1-2 weeks, with a maximum of 6 weeks. Chronic urticaria has a slow onset and recurrent episodes with a duration of more than 6 weeks, months or years. The clusters are sometimes more and sometimes less frequent and are usually not accompanied by systemic symptoms. Acute patients have regular attacks, some in the morning and morning, some in the afternoon or evening. Some patients are associated with environmental factors. Chronic urticaria can be complicated by artificial urticaria, i.e., the skin becomes windy after scratching. The skin scratch test is positive in some cases. Special types of urticaria (1) Peptone urticaria When overeating (over-eating pork and seafood) and mental excitement and drinking a lot of alcohol, the peptone in the food is absorbed and digested, i.e. absorbed by the mucous membrane of the gastrointestinal tract as in the blood, and causes skin redness and wind clumps, with weakness and headache. (2) Cold urticaria can be divided into familial cold urticaria and acquired cold urticaria, which is a physical urticaria caused by cold. (3) Heat urticaria can be divided into acquired and hereditary. (4) Cholinergic urticaria is induced by heat, stress and exercise, mostly on the trunk and proximal extremities, and the rash is a 1-2mm sized cluster surrounded by a red halo. (5) Solar urticaria is more common in women and develops after exposure to sunlight, with the rash confined to the exposed area. (6) Pressure urticaria develops after 4-6 hours of heavy and prolonged pressure, with diffuse, edematous, painful plaques at the site of pressure. (7) Waterborne urticaria Causes small, itchy wind masses around the pores after contact with water and sweat. (8) Seropathic urticaria The cause is an antigen-antibody complex reaction caused by exposure to allogeneic serum, vaccines, drugs, etc. The clinical manifestations are fever, rash, arthritis and lymphadenopathy. (9) Autoimmune progesterone urticaria occurs in the premenstrual and midmenstrual periods and is caused by progesterone. (10) Cutaneous Scratching Patients often have localized itching with wind clusters after scratching.