An Overview of Nipple Discharge

Nipple discharge is very common and rarely dangerous

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Hormones are usually the cause of discharge from the breast. Prolactin, the one that regulates breast milk production, is usually behind it, so nipple discharge is common during pregnancy and breastfeeding. Menstruation, medication side effects, pituitary gland disorders, and excessive breast stimulation can also increase prolactin and cause discharge.

A milky nipple discharge unrelated to pregnancy or breastfeeding is called galactorrhea. It is common in females but can affect males as well.

Certain health conditions can cause a bloody nipple discharge, including a benign (non-cancerous) tumor called a papilloma and, on rare occasions, breast cancer.

This article describes the different types of nipple discharge a person can experience, including the symptoms and causes and how the various conditions are diagnosed and treated.

For the purpose of this article, "females" refers to people born with vaginas and "males" refers to people born with penises irrespective of gender identity or whether they identify with any gender at all.

nipple discharge color
Verywell / Jessica Olah


Nipple discharge can vary in a number of ways. Its qualities can provide clues to the possible causes.

Nipple discharge changes depending on your stage of life, such as whether you're:

  • Premenopausal
  • Postmenopausal
  • Pregnant
  • Breastfeeding

Discharge may occur suddenly and on its own or only when you squeeze the breast or nipple. It may be:

  • Thin and clear
  • Slightly thicker and milky
  • Purulent (pus-like) and cloudy
  • Very thick, sticky, and cheese-like

It comes in many colors:

  • Clear
  • Milky white
  • Yellow
  • Green
  • Brown
  • Red

Nipple discharge may occur on one side (unilateral) or on both sides (bilateral). It may come from a single breast duct or multiple ducts.

If you have symptoms along with discharge, they can be clues to the cause. For example:

  • A fever may suggest a breast infection (mastitis).
  • Missed periods may be a sign of pregnancy or hyperprolactinemia (high levels of the hormone prolactin).
  • A breast mass plus discharge is highly suggestive of breast cancer.

Some of the conditions that cause discharge may also cause breast pain.


Many things can cause breast discharge. Unilateral discharge is more likely with underlying conditions such as:

Bilateral discharge is more likely due to hormonal changes or systemic (body-wide) conditions, such as thyroid disease.

Discharge from a single duct is more likely due to a local condition affecting the breast.

Common Causes

Some of the more common causes include:

  • Pregnancy: Colostrum (pre-breastmilk fluid) may leak before delivery. It's usually thin and light-yellow. It then turns thicker and milky.
  • Breast irritation: Irritation from rough clothing or a poor-fitting bra, or excess stimulation or trauma to the breasts, may cause discharge.
  • Fibrocystic breasts: If you're premenopausal and have fibrocystic breasts (lumpy, possibly painful breast tissue), yellow-green or brown discharge before periods is somewhat normal.
  • Hormonal variation: Normal hormonal changes (e.g., menstruation) may cause nipple discharge. So can prolactin level changes due to a medical condition. That's true no matter your biological sex.
  • Hormone medications: Hormonal drigs (e.g., birth control pills) and sedatives often cause a milky discharge.

Other causes are more serious and may need to be treated.

Nipple Discharge Color Possible Cause(s)*
Clear (serous) Blocked milk ducts, breast cancer
Milky white Breastfeeding, hormone changes, galactorrhea
Yellow Infection
Green Blocked milk ducts, fibrocystic breast disease
Brown Fibrocystic breast disease
Red (bloody) Intraductal papilloma, breast cancer
*These are not the only possible reasons. Only your healthcare provider can determine what's causing your nipple discharge.


Mastitis is a breast infection. It may cause:

  • Pus-like yellow-green discharge
  • Fever
  • Pain
  • Breast tenderness

If the discharge is also foul-smelling, it may be due to an abscess in the nipple or under the areola (pigmented area around the nipple). An abscess is an area the body "walls off" to keep an infection from spreading.

Mammary Duct Ectasia

Mammary duct ectasia means blocked milk ducts. It's most common near menopause (perimenopause) or after menopause. The breast ducts widen and become clogged with thick discharge.

The discharge can be:

  • Green, brown, or black
  • Very thick and cheese-like
  • Accompanied by red, tender nipples

The condition may lead to mastitis. This can cause the nipples to turn inward (nipple inversion), raising breast cancer concerns. 

Mammary duct ectasia usually goes away in time. Hot packs can relieve any discomfort. Some cases require surgery.

Conditions like mammary duct ectasia and cancer become more common during perimenopause and after menopause. Don't dismiss symptoms and be sure your healthcare provider does thorough testing.


A milky discharge can occur in anyone, regardless of sex or age. It resembles breastmilk and is called galactorrhea.

This is most often due to increased levels of prolactin. That's a hormone involved with breast growth and breastfeeding. This condition is called hyperprolactinemia.

Hyperprolactinemia can also make your periods stop (amenorrhea). In biological males, nipple discharge may be the first symptom.

High prolactin levels can come from many causes:

  • Medications: Some blood pressure drugs, opioids, antidepressants, antipsychotics, dopamine antagonists, and acid reflux drugs
  • Herbal supplements: Fenugreek, red clover, anise, and fennel
  • Hypothyroidism: Underactive thyroid gland
  • Pituitary microadenomas: Benign (non-cancerous) growths in the pituitary gland

Intraductal Papillomas

Intraductal papillomas are benign growths that usually involve a single duct. They're most common during premenopause.

They often cause a clear or bloody discharge. You may notice a painless lump on the nipple.

Most aren't a concern. But some may contain regions of papillary carcinoma of the breast. That's a precancerous condition called ductal carcinoma in situ (DCIS).

Breast Cancer

While rare, sometimes nipple discharge is caused by breast cancer. It can be an early warning sign of breast cancer that is still in the pre-invasive stage (DCIS). That's more likely in someone over age 40 and/or if:

  • Discharge is one-sided and spontaneous (without stimulation)
  • Discharge comes from only one duct
  • You have other symptoms of breast cancer (e.g., dimpling, retraction, nipple inversion, or a breast mass)

Discharge from breast cancer can be bloody, clear, or milky.

Paget's Disease

Paget's disease of the breast is an uncommon form of breast cancer. It accounts for less than 3% of cases.

It causes:

  • Nipple discharge that's often bloody
  • Nipple tenderness or burning
  • Redness, scaling, or flaking

It usually takes a biopsy to diagnose this condition.

Male Nipple Discharge

Breast cancer can impact anyone, no matter the sex. Male breast cancer is often under-recognized, even among healthcare providers.

If you're biologically male and have nipple discharge, see your healthcare provider. They may order a mammogram.

Nipple discharge is often an early warning sign of pre-invasive cancer. This is important to remember. Male breast cancer is often diagnosed in later stages than in females. And that makes it harder to treat.

Another reason to not overlook male nipple discharge is that it could be due to elevated prolactin levels. And that can be caused by a pituitary microadenoma (small tumor).

Those are easier to recognize in females because they can make you skip periods. In males, it can go unrecognized until the tumor affects vision by pressing on the optic nerve.

Nipple Discharge in Newborns

In newborns, small amounts of clear or milky nipple discharge is fairly common. It may occur with some breast swelling or a small lump. This is related to hormones leftover from pregnancy.

Later in infancy, bloody discharge may occur. It's usually due to mammary duct ectasia.


Biological males may have nipple discharge from breast cancer or high prolactin levels. Breast cancer in males is often diagnosed at later stages.

Newborns may have discharge due to leftover hormones or mammary duct ectasia.


Your healthcare provider will order tests to diagnose nipple discharge. The specific ones depend on your age, symptoms, and what they find during a physical exam. They include:

  • Blood tests: Prolactin level and thyroid-stimulating hormone (TSH) tests are common.
  • Brain MRI or CT scan: Magnetic resonance imaging (MRI) or computed tomography (CT) scans may be done to check for a pituitary microadenoma.
  • Cytology: A sample of discharge is examined for cancer cells.
  • Ultrasound: Looks for abnormalities behind the nipple and areola. It can identify papillomas. But a biopsy may also be needed.
  • Ductogram: Dye is injected to evaluate breastmilk.
  • Biopsy: A breast biopsy is done to look at lumps near the nipple. A skin biopsy can help diagnose Paget's disease.

If breast cancer is a possibility, a breast MRI, ultrasound, biopsy, and a mammogram may all be considered.


The treatment options for nipple discharge depend on the cause. Some causes, such as discharge in later pregnancy, don't need to be treated.

When it does, treatment may include:

  • Infections are usually treated with antibiotics. An abscess may need to be drained.
  • For fibrocystic disease, aspiration (withdrawing fluid through a needle) of a breast cyst or cysts may resolve the problem.
  • Intraductal papillomas that are symptomatic can be surgically removed.
  • Mammary duct ectasia doesn't usually require treatment other than warm packs to ease discomfort until the condition goes away on its own.
  • Treatment options for breast cancer include surgery, chemotherapy, radiation, and hormone therapy.

Nipple discharge from breast cancer often occurs when the tumor is still very small. Catching it early makes it highly curable.


Nipple discharge can occur in anyone. They're more common around hormonal events like pregnancy and menopause.

The nature of the discharge and other symptoms provide clues to the cause. Some aren't cause for concern. Others may be very serious.

Blood tests, several types of imaging, and an examination of the fluid may be used to diagnose it. Treatment depends on the cause.

A Word From Verywell

Breast cancer is often a concern when there's nipple discharge. Keep in mind that it's more likely to be something else and may not even point to a medical condition.

Both for your health and peace of mind, though, you should get it checked out. The diagnosis may take some time. But it's important to stick with the process even if symptoms appear to go away.

If you're not getting answers, consider a second opinion. Symptoms are our body's way of alerting us to potential problems. It's important to listen.

Frequently Asked Questions

  • Is nipple discharge a sign of pregnancy?

    It can be. Changes to the breasts early in pregnancy can include itchiness, a feeling of fullness, and nipple discharge.

  • Can birth control cause nipple discharge?

    Yes, hormonal changes brought on by your natural cycle or birth control can cause a milky discharge.

  • Is nipple discharge normal during puberty?

    Yes, this is normal and is related to the changing hormones across the monthly cycle.

  • How common is nipple discharge in breast cancer?

    It's not that common. Other benign (innocent) health conditions are more likely to cause nipple discharge. These include a change in hormones or a common infection like mastitis that can happen while breastfeeding.

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Additional Reading
Originally written by Pam Stephan
Pam Stephan is a breast cancer survivor.
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