The cause of itchy red large patches on the body upon scratching is considered to be possible urticaria. Urticaria is a confined edema (windswell) caused by a temporary increase in vascular permeability of the skin’s mucous membranes. The main manifestations are wheals and varying degrees of itching, which may or may not be accompanied by angioedema. Common causes of urticaria include food (plants, animal proteins, food additives, etc.), infections (coxsackie virus, hepatitis viruses, streptococci, etc.), drugs (serum preparations, penicillin antibiotics, etc.), respiratory inhalants, and skin contacts (pollen, animal dander, hair and dust mites, etc.). Psychological factors, endocrine factors, genetic factors and physical factors such as friction and pressure, cold, heat and sunlight can also lead to the development of urticaria. In addition, some systemic diseases such as systemic lupus erythematosus, malignant tumors, ulcerative colitis, etc., can also be accompanied by urticaria. Urticaria should be found in a timely manner to the regular hospital to identify the cause of the disease, under the guidance of the doctor standardized treatment, do not self-medication.