Small red dots on the breasts are painless and itchy, and may be caused by idiopathic thrombocytopenic purpura, liver insufficiency, folliculitis, and so on. 1. Idiopathic thrombocytopenic purpura: If you suffer from idiopathic thrombocytopenic purpura, small red dots may appear due to capillary rupture without pain or itching. 2. Hepatic insufficiency: If you suffer from hepatitis, cirrhosis and other liver diseases leading to hepatic insufficiency, due to the reduction of estrogen inactivation, resulting in capillary dilatation of the spider nevus. 3. Folliculitis: due to poor cleaning and other obstruction of the mouth of the hair follicle, small red dots can appear without pain or itching. In addition, breast eczema, dermatitis and nipple eczema-like breast cancer may also appear similar symptoms, it is recommended that people with small red dots on the breast without pain or itching consult a doctor in a timely manner, to clarify the cause of the disease, and standardize the treatment under the guidance of the doctor.