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 male infants secondary to maternal estrogen exposure

Pregnancy Considerations
Pregnancy stimulates lactotroph cells, so pituitary prolactin-secreting macroadenomas may increase by 21% (1)[A].

Epidemiology

Predominant age: 15 to 50 years (reproductive age)

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 loss of inhibitory regulation by dopamine.
  • Physiologic galactorrhea
    • Nipple stimulation
    • Pregnancy
  • Pathophysiologic galactorrhea
    • Hyperprolactinemia
      • Craniopharyngiomas
      • Irradiation
      • Meningiomas or other tumors
      • Pituitary stalk compression
      • Post-breast augmentation surgery (1%)
      • Prolactinoma (sellar tumor, somatotroph adenoma, pituitary macroadenoma)
      • Traumatic brain injury
      • Vascular malformations (aneurysms)
    • Hyperprolactinemia in systemic disease
      • Adrenal insufficiency
      • Breast tissue with increased sensitivity to prolactin and/or increased prolactin receptors
      • Chronic kidney disease
      • Cirrhosis
      • Graves thyrotoxicosis
      • Hypothyroidism
      • Leukemias (rare)
      • Lung cancer
      • Multiple sclerosis (MS) (with hypothalamic lesion)
      • Renal cell cancer
      • Sarcoidosis/histocytosis
    • Nonhyperprolactinemia
      • Chest wall trauma
      • Chiari-Frommel, del Castillo, and Forbes-Albright syndromes
      • Herpes zoster
      • Spinal cord injury
• 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
  • Illicit
    • Cocaine
    • Marijuana (3)[C]
  • Infectious disease
    • Isoniazid
    • Protease inhibitors
    • Typical and atypical antipsychotics
  • Pain
    • Opioids
  • Psych/neuro
    • Neuroleptics/antipsychotics
    • Stimulants
    • SSRIs, SNRIs (prolactin not always elevated)
    • Tricyclic antidepressants
  • Reproductive
    • Estrogens
    • Copper IUD
• Idiopathic
  • Normal prolactin levels (if patient has galactorrhea plus amenorrhea, likely can have microprolactinoma)

Genetics
No known genetic component

Risk Factors

Certain medications and supplements as above.

General Prevention

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

Commonly Associated Conditions

See “Etiology and Pathophysiology.”