The cause of urticaria is not immunocompromised. Urticaria is a limited edema that occurs in the skin and mucous membranes due to a temporary increase in vascular permeability. Most patients cannot find the exact cause of urticaria, and the common causes include food, infections, medications, respiratory inhalants and skin contacts, physical factors, systemic diseases, psychiatric and immune factors, and genetic factors. 1. Food: such as animal proteins, plants, food additives, etc., can induce urticaria. 2. Infections:such as hepatitis virus, coxsackie virus, streptococcus, fungi, parasites, etc., can induce urticaria. 3. Drugs:such as penicillin antibiotics, serum preparations, and various vaccines, etc., lead to cellular activation through direct interaction between receptors and ligands on the surface of mast cells. 4. Inhalants and contacts: such as pollen, animal dander, hair, dust mites and so on, these substances can induce an allergic reaction, triggering urticaria. 5. Physical factors: such as cold, heat, sunlight, friction, pressure, etc., causing non-immune mechanisms of urticaria. 6. Systemic diseases: such as systemic lupus erythematosus, malignant tumors, metabolic disorders, autoimmune thyroiditis, etc., leading to a decrease in the body’s immune system, which is more likely to induce the occurrence of hyper-immune response, thus triggering urticaria. 7. Mental and immune factors and genetic factors: such as mental tension, too much pressure, low immunity, etc., these factors can induce the occurrence of urticaria. It is recommended that the patient after the occurrence of urticaria, timely and reasonable treatment under the guidance of the doctor, to avoid delaying the condition.