Synonym: lactorrhoea

Galactorrhoea is milky secretion from the breasts. The term usually refers to milk secretion not due to breast-feeding. It is bilateral and from multiple ducts. The milk volume may be large or small, and milk may be secreted spontaneously or expressed.

Physiology of lactation and prolactin¹

Lactation requires prolactin (PRL). Other hormones are involved in priming the breast prior to lactation: oestrogen, progesterone, insulin, thyroid hormones and glucocorticoids. Oxytocin is involved in milk release. Oestrogens and progesterone can also have an inhibitory effect on lactation: the fall in levels after delivery facilitates lactation, whilst an injection of oestrogen was used in the past to inhibit lactation.

Prolactin is unique amongst the pituitary hormones in that it is regulated by an inhibitory factor from the hypothalamus, whilst the other hormones are regulated by a releasing factor. This inhibitor is mainly dopamine. However, thyrotrophin releasing factor (TRF) causes the release of not just thyroid stimulating hormone (TSH) but prolactin too. Hence, acquired hypothyroidism may be associated with elevated prolactin too. Serotonin may also be involved.

There is a physiological increase in prolactin levels in response to: breast stimulation (especially sucking), stress, sleep and post-ictal.²

Epidemiology

Galactorrhoea is much more common in women than in men. In women it may be physiological but in men it is always pathological. Nipple discharge (of any type) accounts for 5% of referrals to a breast clinic, but should not be seen as synonymous with galactorrhoea.³

About a fifth of women with galactorrhoea have pituitary tumours but this rises to around a third if they have amenorrhoea too.⁴

Aetiology¹

Physiological

• Pregnancy and post-lactation: women may lactate from the second trimester, and may continue to produce milk up to 2 years after stopping breast-feeding.
• Fluctuating hormone levels: puberty and the menopause.
• Neonatal: exposure to maternal hormones in utero can produce gynaecomastia and galactorrhoea in the newborn (formerly termed 'witches' milk');⁵ no action is required and it will subside rapidly and spontaneously.
• Nipple stimulation or suckling.

Nonphysiological causes of hyperprolactinaemia

• Prolactinomas (prolactin levels are usually very high in this case).
• Drugs (see 'Drugs that raise prolactin', below).
• Other endocrine disorders:
  • Hypothyroidism
  • Acromegaly
  • Cushing's disease
• Chronic renal failure, liver failure.²
• Chest wall irritation or other irritation at the segmental level T6; for example: injury, shingles, atopic eczema, burns, breast surgery,⁶ gastro-oesophageal reflux⁷, spinal cord injury,⁸ tight-fitting clothes.¹
• Pituitary stalk infiltration or interruption, due to:
  • Sarcoidosis, tuberculosis, or schistosomiasis
  • Multiple sclerosis
  • Resection of the pituitary stalk
• Other malignancies which, rarely, can produce the condition include:
  • Lung cancer
  • Renal adenocarcinoma
  • Hodgkin's lymphoma and T-cell lymphoma
  • Craniopharyngioma
  • Hydatid mole

Presentation

History

• Duration of symptoms, progression, nature, colour and amount of fluid.
• Unilateral or bilateral discharge (unilateral suggests local pathology, and needs breast clinic referral).
• Is it spontaneous or does it have to be expressed?
• When was the last menstrual period? Suspect pregnancy until proved otherwise.
• Drugs: prescribed, over-the-counter and illicit; herbal treatments and dietary supplements.
• Ask about acne, hirsutism, menstrual irregularity, reduced libido, infertility and erectile dysfunction (symptoms of hyperprolactinaemia).
• Thyroid and other endocrine symptoms.
• Ask about headaches, visual symptoms and cranial nerve symptoms (for pituitary tumours).

Examination

• Thyroid gland, signs of hypothyroidism, Cushing's disease or acromegaly.
• Neurological examination including visual fields (if an intracranial or pituitary tumour is suspected).
• Abdominal palpation for pregnancy.
• Examine the breasts:³
  • Can discharge be seen? Does it look milky or bloodstained?. If no discharge is apparent try gently massaging the breasts, or ask the patient to do so herself, to try to express some fluid. Is it bilateral and from multiple ducts?
  • Note any previous breast surgery or abnormality of the surrounding skin.
  • Palpate for lumps and nodes.

Differential diagnosis

Breast disease:¹¹

• Mammary duct ectasia can cause nipple secretions which may be milky or discoloured in appearance. The discharge can be bilateral and from multiple ducts.
• Duct papilloma typically causes serous or bloodstained discharge from a single duct. Underlying malignancy is rare but needs excluding.
• Persistent discharge through a fistula following an abscess.

Investigations¹

Initial investigations:

• Prolactin levels (see separate article Hyperprolactinaemia). Very high levels suggest prolactinoma.
• Thyroid function tests (it is important to exclude hypothyroidism).
• Renal and liver function.
• Pregnancy test if appropriate.

Further investigations may be needed:

• Formal testing of visual fields: defects suggest optic nerve compression and merit urgent referral.
• MRI or CT brain scan - needed, for example, if prolactin levels are significantly raised and not explained by any other cause, or if there is irregular menstruation.
• Other endocrine assessments, e.g. for Cushing's disease or acromegaly, may be appropriate.
• If the nature of breast secretions is unclear, microscopy can show fat globules which are present in milk; Hemastix® can test for blood.³

Management

1. Exclude serious pathology: investigations as above; exclude breast disease.
2. Identify and treat the cause, if possible:
   • Treat hypothyroidism.
   • Management of prolactinomas is described in the separate Hyperprolactinaemia article.
   • Review/change any contributing drugs.
3. If the cause cannot be addressed, consider:
   • Dopamine agonists such as bromocriptine - drug treatment details are also in the Hyperprolactinaemia article (link above).
   • Hormone treatment: testosterone for men or oestrogens for women (e.g. the combined oral contraceptive pill). These help to prevent osteoporosis and may improve symptoms.^12,13
4. When all else has been excluded, what remains is labelled as idiopathic. Female patients with galactorrhoea but normal prolactin levels, normal thyroid function and regular periods can probably be observed.¹

Complications and prognosis

These depend on the underlying cause. There is probably an increased risk of osteoporosis if hyperprolactinaemia is untreated.

Document references

1. Pena KS, Rosenfield JA; Evaluation and Treatment of Galactorrhea. American Family Physician. Vol. 63/No. 9, May 2001
2. Kumar P; Clarke M; Clinical Medicine, 6th Ed, (2005). WB Saunders: London
3. Nipple discharge, Surgical Tutor
4. Edge DS, Segatore M; Assessment and management of galactorrhea. Nurse Pract. 1993 Jun;18(6):35-6, 38, 43-4, passim. [abstract]
5. Madlon-Kay DJ; 'Witch's milk'. Galactorrhea in the newborn. Am J Dis Child. 1986 Mar;140(3):252-3. [abstract]
6. Bentley M, Ghali S, Asplund OA; Galactorrhoea causing severe skin breakdown and nipple necrosis following breast reduction. Br J Plast Surg. 2004 Oct;57(7):682-4. [abstract]
7. Turton DB, Shakir KM; Galactorrhea caused by esophagitis. Am J Obstet Gynecol. 1995 Nov;173(5):1629-30. [abstract]
8. Yarkony GM, Novick AK, Roth EJ, et al; Galactorrhea: a complication of spinal cord injury. Arch Phys Med Rehabil. 1992 Sep;73(9):878-80. [abstract]
9. Melkersson K; Differences in prolactin elevation and related symptoms of atypical antipsychotics in schizophrenic patients. J Clin Psychiatry. 2005 Jun;66(6):761-7. [abstract]
10. Egberts AC, Meyboom RH, De Koning FH, et al; Non-puerperal lactation associated with antidepressant drug use. Br J Clin Pharmacol. 1997 Sep;44(3):277-81. [abstract]
11. Henry & Thompson, Clinical Surgery: second edition. Elsevier Saunders, 2005. ISBN 0702027197
12. Molitch ME; Medication-induced hyperprolactinemia. Mayo Clin Proc. 2005 Aug;80(8):1050-7. [abstract]
13. Gillam MP, Molitch ME, Lombardi G, et al; Advances in the treatment of Prolactinomas. Endocr Rev. 2006 May 26. [abstract]

Internet and further reading

• Rohn RD; Galactorrhea in the adolescent. J Adolesc Health Care. 1984 Jan;5(1):37-49. [abstract]
• Mah PM, Webster J; Hyperprolactinemia: etiology, diagnosis, and management. Semin Reprod Med. 2002 Nov;20(4):365-74. [abstract]
• Tansey MJ, Schlechte JA; Pituitary production of prolactin and prolactin-suppressing drugs. Lupus. 2001;10(10):660-4. [abstract]

Acknowledgements