What Causes Nipple Discharge? Diagnosis and Treatment

By Robynn Lowe
Medically reviewed checkmarkMedically reviewed
May 23, 2022

Nipple discharge is any liquid or fluid coming out of the nipple; this discharge happens either independently or when the nipple is squeezed. 

During the reproductive years, nipple discharge is common and usually not serious.

However, there are times when it can mean something is going on, like an infection, cyst, or cancer. 

This article talks about what nipple discharge is and what can cause it. It also talks about how your medical provider can diagnose the cause and what treatment is available.

Lastly, learn when it’s time to see a doctor.  

What Is Nipple Discharge?

Nipple discharge is when fluid comes out of the nipple part of your breast. Even if you are not pregnant, discharge from your nipple doesn’t usually mean cancer.

However, if discharge is unusual for you, it’s best to let your medical provider know so you can find out the cause. 

50-80% of people with vaginas experience nipple discharge in childbearing years

Sometimes babies have nipple discharge because of the hormones passed from the mom to the baby before birth. The discharge should be gone within two weeks. 

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Types of Nipple Discharge

There are several different colors and consistencies of nipple discharge

Normal looking discharge

Discharge that is most likely normal comes out of both nipples and can happen when you squeeze your nipples.

It is expected to have nipple discharge a few weeks before giving birth, after giving birth, and while nursing.

Discharge that is not normal

Any discharge that has blood in it, only comes from one nipple, or seeps out on its own without squeezing is a sign that something is not right. 

Nipple discharge for males is hardly ever normal and should prompt a medical evaluation.


There are several colors of discharge that you might see.

The color may depend on what is causing the release. For example, the discharge may be clear, milky, yellow, brown, or green. 


There are many non-cancerous causes of nipple discharge. Read on to learn what could be going on. 


Mastitis is when the breast becomes inflamed, usually because of a bacterial infection. It typically happens in breastfeeding people whose duct becomes clogged and then infected. 

Symptoms include:

  • Breast pain
  • Redness
  • Warmth
  • Swelling
  • Nipple discharge


Nipple stimulation, such as sucking, rubbing, or massaging, are common causes of nipple discharge

Mammary duct ectasia (clogged duct)

Mammary duct ectasia is most common in people near menopause or who have just gone through it.

The condition happens when a milk duct under the nipple grows larger and causes the duct to become blocked and fluid to build up.

Most of the time, there are no symptoms, but some people experience thick nipple discharge with some redness and tenderness.  

Fibrocystic breasts

Fibrocystic breasts are painful, lumpy breasts commonly experienced by people about to have their period.

This is normal when breast tissue thickens, and fluid-filled cysts form in one or both breasts; it can make the breasts feel swollen, lumpy, and painful. 

Intraductal papilloma

An intraductal papilloma is a small, non-cancerous tumor that grows inside a milk duct.

It can be tiny and not able to be felt but can cause clear or pink discharge from the nipple.

Typically, the tumor doesn’t cause pain and is discovered by ultrasound or mammogram. In addition, a biopsy can determine that the tumor is non-cancerous. 


Prolactinoma is a small, non-cancerous tumor that grows in the pituitary gland and releases prolactin, a hormone that tells the breasts to produce milk during pregnancy and nursing. 

Symptoms include milky discharge from the nipple, possible changes in your period, and vaginal dryness. 


Hypothyroidism is one of the most common causes of nipple discharge.

When the body has low thyroid hormone levels, it leads to higher levels of prolactin.

Prolactin is the hormone that triggers breast milk production while a person is pregnant and nursing. 

An increased amount of prolactin can cause the breasts to produce a discharge even when not pregnant or nursing. 

Other conditions that lead to increased prolactin levels in the body include: 

  • Chronic renal failure
  • Cushing’s disease 
  • Acromegaly (increased growth hormone)

Breast cancer

Breast cancer is when cells in the breast grow out of control.

The different types of breast cancers depend on what type of cells are growing abnormally. 

Symptoms of breast cancer include:

  • Swelling or thickening of part of the breast 
  • A new lump in the breast or armpit
  • Dimpling or irritation of the skin on the breast
  • Flaking red skin in the nipple area
  • Pulling in or pain in the nipple area
  • Nipple discharge (that is not breast milk)
  • A change in the size or shape of the breast
  • Breast pain


During pregnancy, your breasts may feel larger and lumpier.

They can also be more tender. These changes are because the milk glands are getting larger and preparing for nursing. 

As early as the second trimester, you may notice some clear, milky white, or yellow discharge coming from your nipples.

These are all regular changes caused by hormones as pregnancy progresses.  

The breasts can continue to produce milk up to two years after you stop breastfeeding. 

Certain medications

The following medications may cause nipple discharge as a side effect:

  • Opioids
  • Oral contraceptives
  • Antihypertensives
  • Antidepressants
  • Antipsychotics


Your medical clinician will start with a physical exam, including your history and current medications, and also ask about your family health history. 

Breast exam

For the breast exam, your medical provider will ask you to lay back and help you get comfortable.

Then, the provider first observes the breasts for any possible masses, asymmetry, or changes in the skin. 

Next, they will gently press (palpate) the breasts to check for masses, tenderness, or swelling. 

If there is no discharge visible, they may apply some pressure to the nipple to try and extract some discharge. 

Blood work

Lab work may check for possible infection and could also include:

  • A pregnancy test
  • Prolactin level test
  • Kidney function test
  • Thyroid-stimulating hormone level


If your medical provider is unsure of the cause of your discharge, they may order a mammogram

A mammogram is an x-ray picture of your breasts.

This test can check for early signs of breast cancer. It is beneficial for people with breasts age 40 and above (or sooner, depending on family history) to schedule regular mammograms even when it appears there are no problems. 

Other imaging 

Ultrasound is an excellent tool for looking at breast tissue.

Some research says it is best to use ultrasound and mammogram together because of some limitations of the mammogram. 

If indicated, an MRI of the brain may be completed to look at the pituitary gland. 


Treatment depends on what is causing the nipple discharge. Sometimes no treatment is needed if the cause is normal hormonal fluctuations (fibrocystic breasts and pregnancy). 

If an infection (mastitis) is the reason, your primary medical provider will order antibiotics.

Removing a duct may be necessary for some cases, like mammary duct ectasia and intraductal papilloma.

Your medical provider may order medications in other situations, like hypothyroidism or prolactinoma.

If breast cancer is causing the discharge, surgery, chemotherapy, and radiation may be necessary treatments.

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When To See a Medical Provider

If you are experiencing discharge from your nipples and any of the following symptoms, be sure to see your primary medical provider:

  • A lump in your breast
  • Discharge from only one breast
  • Breast is also red, warm, and swollen
  • Discharge is pink
  • Change in how your breast looks

Also, if you are over the age of 40 and experience nipple discharge, see your medical provider.

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Is it normal to have breast discharge?
Nipple discharge can be a regular occurrence. About half of people with breasts experience benign nipple discharge in their life during reproductive years.
What can cause nipple discharge?
Several things can cause nipple discharge, including hormonal changes before or during your period or pregnancy, infection or blockage of a duct, an increase of prolactin hormone, or breast cancer.
Is it normal to have nipple discharge when not pregnant?
During the reproductive years, it is normal to experience some nipple discharge. However, after the age of 40, it is less common to have nipple discharge, so your medical provider should check any discharge indication.
Does nipple discharge always mean cancer?
No, nipple discharge can be an early sign of cancer; however, there are many other non-cancerous reasons why nipples occasionally have discharge.

K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

Robynn Lowe

Robynn Lowe is a board certified Family Nurse Practitioner with over 15 years in the medical field. Robynn received her Bachelor's and Master's degrees from Florida Atlantic University and has been practicing in rural family medicine since. Robynn is married to her college sweetheart, Raymond and they have three awesome children. When Robynn isn't with patients you can find her shopping, coaching her kids sports teams, or spending time on the water.

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