There are many reasons why nipples are hard when touched, and they are analyzed as follows:1. Premenstrual Syndrome (PMS), nipple hardness, swelling and pain before and during menstruation due to elevated estrogen, nipple symptoms will disappear after menstruation, don’t worry about it.2. Mammary Hyperplasia (MH), patients will have nipple swelling and pain, hardness, breast pain and increased skin temperature during menstruation, and the end of the menstruation symptoms will be relieved, and the pain is obvious. The symptoms will be relieved at the end of menstruation, and the pain can be regulated by taking Easy Pill or Lactaid. 3, nipple allergy, nipple contact with drugs or poor quality cream nipple swelling, pain, itching, you need to stop using the allergic substances, and at the same time, oral antihistamines, prohibit scratching the breasts. 4, neurosis, suffering from depression or anxiety disorders will have somatosensory disorders, which manifested as hardness of nipples or pain, and need to be in the guidance of a professional physician for drug therapy and psychological relief. Psychological counseling.