Why does hyperprolactinaemia cause nipple discharge?

Hyperprolactinaemia causes nipple discharge because excess prolactin signals the breast glands to make and release milk, even when pregnancy or breastfeeding is not present. Nipple Discharge is a common presentation of Hyperprolactinaemia, but discharge can also have other explanations and needs to be assessed in context.

Prolactin is made by the pituitary gland, a small hormone-producing gland at the base of the brain. Its normal role includes preparing the breasts for milk production and supporting lactation after delivery. When prolactin remains higher than expected, the breast tissue may receive a continuing milk-production signal. This may lead to a white or milky fluid from one or both nipples, sometimes without squeezing.

High prolactin may also interfere with the brain signals that regulate the ovaries. Some people notice irregular or absent periods, difficulty becoming pregnant, reduced sexual desire, vaginal dryness, or headaches. Medicines, an underactive thyroid, pregnancy, chest-wall irritation, and a pituitary growth can all affect prolactin, so the discharge alone cannot identify its cause.

Arrange a medical appointment for new, persistent, or unexplained nipple discharge. A clinician may ask whether the fluid is milky, bloody, or clear; whether it comes from one or both breasts; and whether it appears on its own or only after stimulation. They may review medicines and examine the breasts, then request a pregnancy test and blood tests such as prolactin and thyroid testing. Further testing is guided by the findings.

Avoid repeatedly checking or squeezing the nipple, because stimulation can encourage more discharge. Do not stop a prescribed medicine without advice; some medicines can raise prolactin, and a clinician can discuss a safe adjustment if needed.

Seek prompt medical assessment if the discharge is bloody or clear, comes from one breast or one duct, appears without touching the nipple, or occurs with a new lump, skin or nipple change, redness, swelling, or significant pain. A severe or new headache, vision changes, or symptoms suggesting pregnancy also warrant timely advice. These features do not establish a diagnosis, but they help determine how quickly you should be examined.

You could ask: Could pregnancy, a medicine, thyroid changes, or another condition be affecting my prolactin? Do I need a repeat prolactin test under specific conditions? What symptoms would mean I should seek urgent help? If treatment is recommended, how will we monitor the discharge and my hormone levels?