The following factors are related to the darkening of nipples: 1, genetics or disease lead to darkening of nipples, if the patient has endocrine diseases, not only in the susceptibility to facial melasma, breast lumps and uterine fibroids, the corresponding nipples will also become dark, but also may cause immune system diseases, osteoporosis, hyperlipidemia and other diseases, and the root cause of these diseases is endocrine disorders, treatment should also be from the balance of endocrine disorders.