What Is Galactorrhea?

  • Asra RunissaMaster of Science - MS, medical biochemistry Kasturba Medical College, Mangalore
  • Sofiya StarBSc.Hons Medical Sciences, University of Edinburgh, Scotland
  • Katheeja ImaniMRes Biochemistry, University of Nottingham, UK


Prolactin is a hormone produced from lactotroph cells in the anterior pituitary gland, a pea-sized gland present at the base of the brain. It is responsible for the synthesis of breast milk. It is also crucial for the development of breast tissue and the induction of lactation.

Galactorrhea is a condition in which there is milk production, or unwanted nipple discharge, from the breast that is not associated with pregnancy or lactation. Unwanted nipple discharge is common amongst people assigned female at birth (AFAB) of reproductive age. This is known as galactorrhea. It often occurs due to an underlying cause, mainly hyperprolactinemia, a pituitary gland tumour, chronic kidney disease, hypothalamic lesions and adverse effects of medication. Various hormones, such as prolactin, oestrogen, and thyrotropin-releasing hormone (TRH), have an influence on causing galactorrhea.1 Galactorrhea can also be observed in people assigned male at birth (AMAB) and in infants.

Causes of galactorrhea

The underlying causes of galactorrhea can be classified into two categories:

  • Hypothalamic-pituitary causes
  • Non-hypothalamic-pituitary causes

Hypothalamic-pituitary causes

Hypothalamic-pituitary causes of galactorrhea are mainly characterised by a defect in the production and secretion of pituitary gland hormones due to a benign (non-cancerous) tumour in the pituitary gland or in the hypothalamus. These tumours are called prolactinomas. Prolactinomas are prolactin-secreting tumour growths. Depending on the size of the tumour, the production of prolactin hormone can vary;  larger tumours correlate with a higher prolactin level in the blood. When an individual has prolactin levels that exceed the normal range, it is described as hyperprolactinemia. Tumours in the pituitary gland directly control the secretion of prolactin, leading to hyperprolactinemia. This happens because tumours can physically compress nearby anatomical structures, like the pituitary stalk, to prevent prolactin secretions from being inhibited by feedback loops.2 

Non-hypothalamic-pituitary causes:

Non-hypothalamic-pituitary causes of galactorrhea are not associated with hypothalamus and pituitary gland problems. Instead, they include:

  • Pregnancy
  • Hypothyroidism (underactive thyroid gland)
  • Use of dopamine-inhibiting medication, such as antipsychotic and antidepressant drugs, as they reduce the amount of dopamine available to inhibit prolactin secretion 
  • Use of birth control pills containing high doses of oestrogen 
  • Intake of herbal supplements, such as fenugreek seed, anise or fennel
  • Chronic kidney disease
  • Hyperprolactinemia without any known cause (idiopathic galactorrhea)
  • Nipple stimulation
  • Sexual activity
  • Chest injury

Signs and symptoms of galactorrhea

The symptoms associated with increased prolactin levels are:3

  • Menstrual irregularities (amenorrhea)
  • Decreased libido (decreased sexual activity)
  • Erectile dysfunction
  • Infertility
  • Headaches and visual deficits in case of pituitary lesions

Diagnosis of galactorrhea

History and physical examination

Galactorrhea is diagnosed upon physical examination and by going through the history of the patient.4 The physical examination procedure is comprised of a patient being made to sit upright, leaning forward. The areola, the skin surrounding the nipple, is then squeezed forward and assessed for any kind of unwanted nipple discharge. Galactorrhea appears as a milky discharge, sometimes green in colour. Bloody discharge and breast enlargement can be observed in breast cancer. A pregnancy test has to be done to rule out if galactorrhea is the result of a pregnancy. Breast milk has a high-fat content, so nipple discharge can be tested for the presence of lipid droplets by a process known as Sudan IV staining to confirm that the discharge is milk.

Excessive breast stimulation or nipple stimulation, such as that which may occur during sexual activity, can result in breast discharge that is not indicative of galactorrhea.

Diagnostic test

Prolactin level is measured by a blood test to rule out hyperprolactinemia. Hormones other than prolactin, such as thyroid hormone and oestrogen,  can also be assessed to understand the underlying cause. A renal function test can be conducted if chronic kidney disease is suspected. Magnetic resonance imaging (MRI) of the pituitary gland can help identify pituitary tumours and other lesions. Mammography, ultrasound or both are required for the detection of breast tumours.

Management and treatment for galactorrhea

Management and treatment of galactorrhea are done by targeting the underlying cause. Treatment aims to lower the prolactin levels in the blood of the affected individual. Dopamine agonists can inhibit prolactin production and help in lowering prolactin levels. When treating galactorrhea, mental health medication needs to be stopped so that it does not interfere with the actions of dopamine agonists.

Risk factors

Individuals with thyroid disorders, pituitary tumours, and chronic renal issues are at higher risk of experiencing galactorrhea


A quarter of patients who experience abnormal breast discharge are diagnosed with breast cancer, which requires further screening.5


How can I prevent galactorrhea?

There is no prevention strategy, but treating the underlying cause can help stop galactorrhea since it is a symptom and not a condition.

How common is galactorrhea?

Galactorrhea is the third most common breast-associated problem. It affects 1 out 5 AFABs.

When should I see a doctor?

If you are not pregnant or breastfeeding but start observing milky nipple discharge or other kinds of breast discharge that do not subside, consult a family physician.


Galactorrhea is a condition in which breast discharge that is not associated with lactation or pregnancy is seen. The possible causes are hyperprolactinemia, pituitary gland tumours, chronic kidney disease, hypothalamic lesions and adverse effects of medication and birth control pills. Diagnosis is mainly achieved through physical examination, blood tests, MRI and ultrasound. Treatment involves the usage of drugs that reduce prolactin levels in the blood and resolve the underlying cause of galactorrhea. If you notice any nipple discharge when you are not pregnant, please visit your healthcare provider. 


  1. Gosi SKY, Garla VV. Galactorrhea. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 [cited 2023 May 7]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK537115/
  2. Fukuhara N, Nishiyama M, Iwasaki Y. Update in pathogenesis, diagnosis, and therapy of prolactinoma. Cancers (Basel) [Internet]. 2022 Jul 24 [cited 2023 May 7];14(15):3604. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9331865/
  3. Samperi I, Lithgow K, Karavitaki N. Hyperprolactinaemia. J Clin Med [Internet]. 2019 Dec 13 [cited 2023 May 7];8(12):2203. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6947286/
  4. Salzman B, Collins E, Hersh L. Common breast problems. afp [Internet]. 2019 Apr 15 [cited 2023 May 7];99(8):505–14. Available from: https://www.aafp.org/pubs/afp/issues/2019/0415/p505.html 
  5. de Paula IB, Campos AM. Breast imaging in patients with nipple discharge. Radiol Bras [Internet]. 2017 [cited 2024 Jan 3];50(6):383–8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5746883/ 
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Asra Runissa

Master of Science - MS, medical biochemistry Kasturba Medical College, Mangalore

I am Asrarunissa from India. I hold a bachelor's degree in Biomedical science from Nitte university and M.Sc. in Medical Biochemistry from Manipal university. I was been working as a biochemistry lecturer for Physiotherapy students. I love to build my knowledge and also impart it to those who require it, which is what exactly I m doing right now being a medical writer at Klarity. Dedicating ample amount of time, to researching and developing an article that ultimately benefits society at large.

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