1. Physiological factors: During the pregnancy, the body is affected by the changes in the level of estrogen, which can lead to the woman’s breast hair, which is a normal physiological phenomenon. 2. Mastitis: common in breastfeeding women, usually due to bacterial infection or milk stagnation, caused by inflammation of the mammary gland, in the inflammation of the stimulation effect, may cause the milk hair purple, may also be accompanied by breast swelling, pain and other symptoms. 3. Nipple tumor: this disease belongs to a benign tumor, usually due to local stimulation, inflammation or viral infection and other reasons, can lead to abnormal proliferation of epithelial cells in the affected area, thus forming a round swelling in the nipple area, and in severe cases, can lead to the surface of the swelling rupture and bleeding, which can cause the milk hair purple. At the same time, high estrogen, genetic factors, breast tumors, skin diseases can also appear nipple purple. There are many causes of nipple purple, it is recommended to go to the regular hospital immediately after the discovery of nipple purple, after a clear diagnosis, under the guidance of the doctor standardized treatment.