Itchy nipples at night are mostly considered to be caused by breast diseases, infectious factors, endocrine factors and other reasons. 1. Breast Disease: Itchy nipples at night does not exclude that it is caused by breast disease, such as breast hyperplasia. This phenomenon may be induced when the ratio of female estrogen to progesterone is imbalanced, the quality and quantity of mammary sex hormone receptors are abnormal, the development is abnormal, and the lactation function is abnormal. Especially at night, the nerves will be more sensitive than during the day, so it will be obvious that the nipples itch at night. 2. Infection factors: If women wear underwear material is not suitable, such as chemical fiber material will lead to excessive friction of the breast, which will induce nighttime nipple itching situation is more obvious. In addition, the nipple skin is dry or rough for a long time and other related reasons, will induce bacterial growth, when infection occurs, it will also show the symptoms of nighttime nipple itching. 3. Endocrine factors: If a woman is pregnant, before or after menstruation, mental stimulation, staying up all night and other problems, it will induce endocrine disorders, which will lead to more obvious nipple itching at night. There are many other symptoms that can induce nipple itching at night, such as milk accumulation, nipple breakage, mastitis and other problems that can induce this phenomenon. It is recommended that patients should go to the local hospital in time to find the problem and treat it as soon as possible.