The main causes of sore and itchy nipples include the following: 1. caused by dilated milk ducts, which are often caused by papillomas in the milk ducts. This lesion can easily cause nipple overflow, and the long-term presence of overflow will stimulate the nipple to produce pain and itchiness. 2. Inflammatory diseases of the nipple itself, mostly related to eczema of the nipple, need to go to the dermatology department of the hospital to determine the diagnosis. 3. Special types of breast cancer, clinically known as Paget’s disease, need to go to the hospital to undergo pathological biopsy of the nipple. 4. 5. A physiological defect is nipple invagination, which can easily cause local residual secretions and stimulate this clinical reaction later.