How does allergic urticaria cause

Urticaria is an allergic disease caused by many causes, sometimes difficult to determine, especially chronic urticaria, common food, drugs, such as heterologous protein fish, shrimp, shellfish or drugs, such as penicillin, furazolidone or serum products. Infection can also cause urticaria manifestations, such as upper respiratory tract infections, especially streptococcal infections, and children with acute urticaria is closely related. Chronic patients may also be related to Helicobacter pylori infection in the digestive tract. Fungi and viruses can also cause urticaria manifestations. Some plant pollen, dust mites, feathers, formaldehyde, animal dander, or some insect repellent powder can cause urticaria manifestations. In addition, hot and cold stimuli, some chemicals, or systemic diseases, such as lupus erythematosus, thyroiditis, etc. can cause urticaria.