Description

• Milky nipple discharge not associated with gestation or present >1 year after weaning. Galactorrhea 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 to 35

Incidence
Prolactinomas, as a cause of galactorrhea, have a 44.4 persons per 100,000 incidence in adults (2).

Prevalence
Third most common breast complaint in women. 20–25% of women experience galactorrhea in their lifetime (3)[C].

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/histocytosis)
    • 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) (4)[C]
  • Herbal (anise [liquorice], barley, blessed thistle, fenugreek seed, fennel, goat’s rue)
  • Illicit (cocaine, marijuana) (3)[C]
  • Anti-infectives (isoniazid, protease inhibitors)
  • Opioids
  • Psych/neuro (neuroleptics, antipsychotics, stimulants, SSRIs, SNRIs [prolactin not always elevated], tricyclic antidepressants)
  • Reproductive (estrogens, copper IUD)
• Normal prolactin levels (if patient has galactorrhea plus amenorrhea, likely can have microprolactinoma)

General Prevention

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

Commonly Associated Conditions

See “Etiology and Pathophysiology.”