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Galactorrhea (also spelled galactorrhoea) (galacto- + -rrhea) or lactorrhea (lacto- + -rrhea) is the spontaneous flow of milk from the breast, unassociated with childbirth or nursing. Galactorrhea is reported to occur in 5–32% of women. Much of the difference in reported incidence can be attributed to different definitions of galactorrhea. Although frequently benign, it may be caused by serious underlying conditions and should be properly investigated. Galactorrhea also occurs in males, newborn infants and adolescents of both sexes. ==Causes== It can be due to dysregulation of certain hormones or local causes such as excessive nipple stimulation. Hormonal causes most frequently associated with galactorrhea are hyperprolactinemia and thyroid conditions with elevated levels of thyroid-stimulating hormone (TSH) or thyrotropin-releasing hormone (TRH). No obvious cause is found in about 50% of cases.〔 Lactation requires the presence of prolactin, and the evaluation of galactorrhea includes eliciting a history for various medications or foods (methyldopa, opioids, antipsychotics, serotonin reuptake inhibitors, as well as licorice) and for behavioral causes (stress, and breast and chest wall stimulation), as well as evaluation for pregnancy, pituitary adenomas (with overproduction of prolactin or compression of the pituitary stalk), and hypothyroidism. Adenomas of the anterior pituitary are most often prolactinomas. Overproduction of prolactin leads to cessation of menstrual periods and infertility, which may be a diagnostic clue. Galactorrhea may also be caused by hormonal imbalances owing to birth control pills. Galactorrhea is also a side effect associated with the use of the second-generation H2 receptor antagonist cimetidine (Tagamet). Galactorrhea can also be caused by antipsychotics that cause hyperprolactinemia by blocking dopamine receptors responsible for control of prolactin release. Of these, risperidone is the most notorious for causing this complication. Case reports suggest proton-pump inhibitors have been shown to cause galactorrhea. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Galactorrhea」の詳細全文を読む スポンサード リンク
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