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

Pregnancy Considerations

• Pregnancy stimulates lactotroph cells, so pituitary prolactin-secreting macroadenomas may increase by 21% (1)[A].
• 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 20–35; third most common breast complaint in women

Incidence
Marked variability reported

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

Etiology and Pathophysiology

• Oxytocin stimulates prolactin secretion, which induces lactation. Prolactin is secreted by the anterior pituitary and inhibited by dopamine produced in the hypothalamus.
• Galactorrhea results either from prolactin overproduction or from loss of inhibitory regulation by dopamine.
• Physiologic galactorrhea is due to pregnancy or from nipple stimulation, piercing.
• Pathophysiologic galactorrhea
  • Hyperprolactinemia (craniopharyngiomas, other tumors; irradiation; traumatic brain injury; pituitary stalk compression; postbreast augmentation surgery [1%]; prolactinoma [sellar tumor, somatotroph adenoma, pituitary macroadenoma]; vascular malformations [aneurysms])
  • Hyperprolactinemia in systemic diseases (adrenal insufficiency, chronic kidney disease, cirrhosis, thyroid disease, lung cancer, renal cell cancer, sarcoidosis/histiocytosis)
  • Nonhyperprolactinemia
    • Chest wall trauma; spinal cord injury
    • Chiari-Frommel, del Castillo, and Forbes-Albright syndromes
    • Herpes zoster
• Medications/substances:
  • Cardiovascular (α-methyldopa, reserpine, verapamil, spironolactone)
  • GI (domperidone, H₂ blockers, metoclopramide, proton pump inhibitors) (2)[C]
  • Herbal (anise [licorice], barley, blessed thistle, fenugreek seed, fennel, goat’s rue)
  • Illicit (cocaine, marijuana)
  • Anti-infectives (isoniazid, protease inhibitors)
  • Opioids
  • Psych/neuro (neuroleptics, antipsychotics, stimulants, SSRIs, SNRIs [prolactin not always elevated], tricyclic antidepressants, MAOIs) (3)[C]
  • Reproductive (estrogens, copper IUD)
  • DMARDs (azathioprine)
• Normal prolactin levels (if patient has galactorrhea plus amenorrhea, likely can have microprolactinoma)

Risk Factors

See “Etiology and Pathophysiology.”

General Prevention

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

Commonly Associated Conditions

See “Etiology and Pathophysiology.”