The appearance of white material in the center of the nipple is mainly considered to be caused by the production of milk. If the symptoms of itchy skin appear at the same time, it is necessary to consider the presence of bacteria or mold. The patient needs to remove the white stuff in the middle of the nipple, and then observe whether it reappears or not. Meanwhile, after removing the white stuff, you can squeeze the nipple to see whether there is a discharge of the same color. If it is white, it is milk, which is most common in women who have breastfed. If you are not breastfeeding, the discharge is from the ducts of the mammary glands and does not need to be treated if there are no uncomfortable symptoms, but you need to keep your nipples clean and hygienic. Warm water can be used to clean the nipples, and the milk should be emptied after breastfeeding to minimize the occurrence of mastitis. If nipple inversion occurs, you need to pull out the nipple to keep it clean and hygienic.