Red spots on the waist may be caused by insect bite reaction, vascular nevus, cherry angioma and other diseases. 1. Insect bite reaction: the cause of the disease is mainly related to the allergic reaction after insect bites. Patients will have localized erythema, blisters and other symptoms, which are more common in the waist, buttocks and limbs and other parts of the body. 2. Vascular nevus: the cause of the disease is mainly related to the abnormal development of blood vessels, obesity, endocrine, drugs and other reasons can also induce the disease. Red papules and nodules will appear locally, mostly in trunk, limbs, head and face. 3. Cherry angioma: the cause of the disease is not clear, may be related to aging, gene mutation and other factors. Patients will have purple-red or bright red papules and nodules locally, which are mostly found in the trunk, upper limbs and other parts of the body. There are more reasons for red spots on the waist, and it is recommended that regular hospitals visit the doctor for examination to clarify the cause.