ContentsSynopsisCodesLook ForDiagnostic PearlsDifferential Diagnosis & PitfallsBest TestsManagement PearlsTherapyDrug Reaction DataReferencesView all Images (3)
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Contributors: Laurie Good MD, Whitney A. High MD, JD, MEng, Lowell A. Goldsmith MD, MPH
Other Resources UpToDate PubMed


Galactorrhea is simply inappropriate lactation, and it is not representative of a specific disease but rather is a sign of an underlying condition. It is caused by increased levels of prolactin; prolactin levels are controlled by the hypothalamus through positive and negative feedback of the pituitary gland. Galactorrhea can result from stimulation of the nipple, medications, sexual intercourse, stress, hypothyroidism, or a prolactin-secreting pituitary adenoma (prolactinoma). Very rarely, those who do not produce milk (agalactia) may have an abnormality of prolactin receptor. Lactation is considered physiologic in pregnant individuals after the first trimester as well as up to 2 years after cessation of breastfeeding.

Galactorrhea is relatively common in women: as many as 20%-25% of all women are affected at some point in their lives. Men can rarely have galactorrhea, most often from medications.

Galactorrhea may occur unilaterally or bilaterally. The discharge can have different colors (white, yellow, or green). Typically, blood is not present.  

Risk factors for galactorrhea include the use of medication from certain classes (most commonly antipsychotics with antidopaminergic properties), as well as other medical conditions, such as hypothyroidism, hypothalamic-pituitary disorders, and chest wall irritation.

Pediatric Patient Considerations:
Galactorrhea can be physiologic in the first month of life.


O92.6 – Galactorrhea

78622004 – Galactorrhea not associated with childbirth

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Diagnostic Pearls

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Differential Diagnosis & Pitfalls

It is important to note that galactorrhea – when not physiological – is an outward manifestation of some other endocrine or medication-based abnormality; therefore, the differential diagnosis of galactorrhea includes a variety of disorders and conditions:
  • Pregnancy – Pregnancy should always be considered. Unless the patient is postmenopausal or has had a hysterectomy, a pregnancy test is indicated.
  • Prolactinoma – A pituitary tumor can secrete excess prolactin; may be identified on MRI of the brain.
  • Medication side effect – Particularly with antipsychotic medications, but galactorrhea may also be seen with other medications and some herbal supplements.
  • Hypothyroidism – May result in secondary hyperprolactinemia; detected by high thyrotropin level and low T4 level.
  • Cushing disease – Hypercortisolism may result in secondary hyperprolactinemia; determined with 24-hour urine cortisol level.
  • Acromegaly – Increased growth hormone from the pituitary may be associated with hyperprolactinemia; determined with serum growth hormone level.
  • Chest wall irritation – Chest wall irritation from clothing or ill-fitting brassieres, herpes zoster, or atopic dermatitis may produce galactorrhea, as may breast implant surgery or reduction mammoplasty.
  • Excessive nipple stimulation

Best Tests

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Management Pearls

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Drug Reaction Data

Below is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.

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Last Updated:08/05/2021
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Galactorrhea : Nipple discharge, Prolactin level increased, Hyperprolactinemia
Clinical image of Galactorrhea
A grayish milky discharge at the nipple.
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