• Milky nipple discharge not associated with lactation, defined as >1 year after pregnancy or cessation of breastfeeding.
  • Does not include serous, purulent, or bloody nipple discharge
  • System(s) affected: endocrine/metabolic, nervous, reproductive

Pediatric Considerations
Can occur in infants secondary to maternal estrogen exposure

Pregnancy Considerations
Milk production often begins during the second trimester; milk leakage that occurs during pregnancy is not pathophysiologic galactorrhea.


  • Predominant age: 15 to 50 years (reproductive age), most commonly ages 20 to 35 years
  • Third most common breast complaint in women

Marked variability reported

Approximately 20–25% of women experience galactorrhea in their lifetime.

Etiology and Pathophysiology

  • Oxytocin stimulates the anterior pituitary to secrete prolactin, which induces lactation.
  • Prolactin secretion is inhibited by dopamine produced in the hypothalamus.
  • Galactorrhea results either from prolactin overproduction or loss of inhibitory regulation by dopamine.
  • Physiologic galactorrhea can be due to pregnancy, nipple stimulation, nipple piercing, exercise, or sexual activity.
  • Hyperprolactinemia can be due to overproduction by malignancy or mass effect, most commonly prolactinoma.
  • Hyperprolactinemia secondary to systemic diseases:
    • Hypothyroidism
    • Chronic renal failure (reduced clearance of prolactin leading to elevated serum levels)
    • Cirrhosis
    • Adrenal insufficiency
  • Medications/substances:
    • Cardiovascular (α-methyldopa, reserpine, verapamil, spironolactone)
    • GI (domperidone, metoclopramide)
    • Herbal (anise [licorice], barley, blessed thistle, fenugreek seed, fennel, goat’s rue)
    • Illicit (cocaine, marijuana)
    • Antimicrobials (isoniazid, protease inhibitors)
    • Opioids
    • Psych/neuro (neuroleptics, antipsychotics, stimulants, SSRIs, tricyclic antidepressants, MAOIs)
    • Reproductive (estrogens, copper IUD)
    • DMARDs (azathioprine)

General Prevention

  • Avoid frequent nipple stimulation.
  • Avoid medications that can suppress dopamine.

Commonly Associated Conditions

  • Commonly associated with hypothyroidism, chronic kidney disease, hypogonadism, and pituitary adenoma
  • Rarely associated with adrenal insufficiency, chest wall conditions/trauma, post-breast reduction surgery, acromegaly

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