Nipple discharge is any fluid or other liquid that comes out of your nipple. You might have to squeeze the nipple to get the fluid to come out, or it could seep out on its own.

Nipple discharge is common during your reproductive years even if you’re not pregnant or breastfeeding. Discharge is usually not serious. Still, it can be a sign of breast cancer, so it’s worth seeing your doctor about.

Keep reading to learn more about the different types of nipple discharge and when you should talk to your doctor.

Nipple discharge comes in many different colors. The color can give you some clues about the cause. The chart below lists the discharge colors and some possible causes in women who aren’t lactating. You can learn more about these causes in the next section.

ColorPossible cause
white, cloudy, yellow, or filled with pusan infection of the breast or nipple
greencysts
brown or cheese-likemammary duct ectasia (blocked milk duct)
clearbreast cancer, especially if it’s only coming from one breast
bloodypapilloma or breast cancer

Discharge can also come in a few different textures. For example, it may be thick, thin, or sticky.

The discharge might come out of just one nipple or both nipples. And it can leak out on its own or only when you squeeze the nipple.

Some other symptoms you might have with the nipple discharge include:

  • breast pain or tenderness
  • lump or swelling in the breast or around the nipple
  • nipple changes, like turning inward, dimpling, color changes, itching, or scaling
  • redness
  • breast size changes, such as one breast that’s larger or smaller than the other
  • fever
  • missed periods
  • nausea or vomiting
  • fatigue

When you’re pregnant or breastfeeding, small amounts of milk might leak out of your breasts. The leakage can start early in your pregnancy and you could continue to see milk for up to two or three years after you stop breastfeeding.

However, women who aren’t pregnant or breastfeeding may have discharge as well. Other causes of nipple discharge include:

  • birth control pills
  • breast infection or abscess
  • duct papilloma, a harmless wart-like growth in your milk duct
  • drugs that increase levels of the milk-producing hormone prolactin, such as antidepressants and tranquilizers
  • excess stimulation of the breast or nipple
  • fibrocystic breasts
  • hormone changes during your period or menopause
  • injury to the breast
  • mammary duct ectasia, a blocked milk duct
  • prolactinoma, a noncancerous tumor of the pituitary gland
  • underactive thyroid gland
  • breast cancer

Breast cancer can cause nipple discharge, especially ductal carcinoma in situ (DCIS), an early form of breast cancer that starts in the milk ducts. It can also happen with Paget disease of the breast, a rare type of breast cancer that involves the nipple.

If you do have breast cancer, the discharge will probably only come from one breast. You’ll likely have a lump in your breast, too.

Discharge is rarely due to cancer, however. Only about 3 to 9 percent of people who see a doctor for this symptom actually turn out to have cancer. Still, it’s a good idea to get any breast discharge checked out, especially if it’s a new symptom for you.

Learn more: Warning signs of breast cancer »

Nipple discharge is usually nothing to worry about. Still, because it can be a sign of breast cancer, see your doctor to have it checked out. It’s especially important to see a doctor if:

  • you have a lump in your breast
  • you have nipple changes (such as crusting or color change)
  • you have pain in your breast or other symptoms of breast cancer
  • the discharge is bloody
  • only one breast is affected
  • the discharge doesn’t stop

Your doctor will start by asking questions about the discharge, including:

  • When did the discharge start?
  • Is it in one breast or both?
  • Does it come out on its own, or do you have to squeeze the nipple to produce it?
  • What other symptoms do you have?
  • What medications do you take?
  • Are you pregnant or breastfeeding?

The doctor will do a clinical exam to check your breasts for lumps or other signs of cancer. You may also have one or more of these tests:

  • Biopsy: The doctor removes a small sample of tissue from your breast to check it for cancer.
  • Mammogram: This test takes X-ray pictures of your breasts to help the doctor look for cancer.
  • Ductogram: This test uses mammography and an injected contrast material to make pictures of the milk ducts inside your breasts.
  • Ultrasound: This test uses sound waves to make pictures of the inside of your breasts.

Your doctor will also likely do a urine or blood test to find out whether you’re pregnant.

Keep reading: More about breast cancer detection »

Once you know what’s causing the nipple discharge, you can treat it if necessary. Discharge that’s due to pregnancy, breastfeeding, or hormonal changes doesn’t need to be treated. Your doctor will treat discharge from other causes based on the condition.

Learn more: Breast cancer treatment options by stage »