Itchy nipples before menstruation may be related to changes in hormone levels, inadequate cleansing, friction stimulation, nipple inflammation, nipple eczema and other factors. 1. Changes in hormone levels: When a woman is about to have her period, the hormone levels in her body will change, and she may experience swelling and pain in her breasts, or pain or itching in her nipples, and the symptoms will usually improve after her period is over. 2. Inadequate cleaning: If you don’t pay attention to the cleanliness and hygiene of the breast skin, and don’t clean it in time after sweating, the fermentation of sweat may irritate the local skin, and the symptom will appear. 3. Friction stimulation: If you wear a tight bra or a bra that is not breathable, it may also cause friction stimulation to the local skin, resulting in itching symptoms. 4. Nipple inflammation: Nipple inflammation is usually caused by bacterial invasion, which is manifested as red, swollen, hard and enlarged nipples, accompanied by nipple pain or itching. 5. Nipple eczema: Eczema is a skin disease that often occurs in moist, poorly ventilated parts of the skin, or moist and unclean environments, which destroys the barrier ability of the nipple skin, exposes the skin inside the nipple, and comes into contact with allergens or unclean items, thus causing chronic inflammation of the nipple related to allergic reactions. If the symptoms are obvious, you can visit the hospital for standardized examination and treatment.