Red spots on the waist accompanied by itching symptoms can usually be considered as contact dermatitis, pressure urticaria, erythema scaly disease, etc. 1. Contact dermatitis: some patients who are allergic to pants buttons, metal buckles, belt buckles, in contact with such substances, the waist skin will appear with obvious itching red macules, well defined erythema, etc., often diagnosed as contact dermatitis. 2. Pressure urticaria: this kind of disease is a common cause of red itchy spots on the waist. The waist is often tied pants, belt parts, and the waist skin by excessive strangulation, it is easy to appear local flushing and doughnut damage, often called pressure urticaria. Usually, after the patient lifts the pants belt or belt, such lesions can subside. 3. Erythematous scaly diseases: such as psoriasis, pityriasis rosea, chronic mossy chaff rash and other erythematous scaly diseases can also show localized skin erythema accompanied by itching and other symptoms. It is recommended that patients with expanding red spots, accompanied by severe itching, go to the dermatology department of regular hospitals in a timely manner, to clarify the cause of the disease, and then follow the doctor’s instructions to choose the appropriate treatment program.