Description

• 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; advise parents not to palpate and not to express milk (colloquially called “witches milk”).Pregnancy Considerations
Milk production often begins during the 2nd trimester; milk leakage that occurs during pregnancy is not pathophysiologic galactorrhea.

Epidemiology

• Predominant age: 15 to 50 years (reproductive age), most commonly ages 20 to 35 years
• Third most common breast complaint in women
• Men with prolactinomas may present with shorter duration of symptoms, higher prolactin levels, and larger more resistant tumors.

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
• Acupuncture has also been shown to cause galactorrhea.
• Medications/substances:
  • Cardiovascular (α-methyldopa, reserpine, verapamil, spironolactone)
  • GI (domperidone, metoclopramide, rabeprazole)
  • Herbal (anise [licorice], barley, blessed thistle, fenugreek seed, fennel, goat’s rue)
  • Illicit (cocaine, marijuana)
  • Antimicrobials (isoniazid, protease inhibitors)
  • Opioids
  • Psych/neuro (neuroleptics, antipsychotics [notably risperidone], stimulants, SSRIs, tricyclic antidepressants, MAOIs)
  • Reproductive (estrogens depot-medroxy-progesterone acetate [DMPA], copper IUD)
  • DMARDs (azathioprine)
• Rarely associated with adrenal insufficiency, post-breast reduction surgery, acromegaly, or wall conditions (such as trauma, burns, herpes simplex virus [HSV] pain in nipple/areolar dermatome); infiltrative diseases of the pituitary gland can also rarely lead to galactorrhea.

Risk Factors

• Hypothyroidism
• Use of medications that cause galactorrhea (see above list)

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