When To Be Concerned About Nipple Discharge

What to know about each type of nipple discharge.

When you think about a body part that leaks, you probably don't think of your nipples—but leaking fluid from the breasts is more common than you might think.

According to the National Library of Medicine (NLM), 50% to 80% of people with breasts who aren't pregnant or breastfeeding experience discharge from their nipples. While most causes are benign, it's important to be aware of the different types of nipple discharge so you can take care of your health.

Anatomically, breasts are meant to contain fluid. Along with fatty tissue, every breast contains around 15 to 20 milk ducts, which are like routes from the inside of the breast to the nipple, according to the NLM. "This is the part of the breast that brings fluid to the nipple and could result in discharge," said Carla Fisher, MD, director of breast surgical oncology at Indiana University Health.

If you're not breastfeeding, you can still experience discharge from one or both nipples. Some types of nipple discharge are unproblematic, but you should get checked out by a healthcare provider if you are experiencing other types or are unsure. Here's how to tell the types apart.

Physiologic Nipple Discharge

Broadly, Dr. Fisher said, there are two types of nipple discharge. Physiologic discharge is normal discharge the body produces, and pathologic discharge indicates a disease process.

Physiologic discharge is usually related to something systemic that is going on in a person's body. Typically, it comes from both breasts and can come out of multiple ducts (which Dr. Fisher described as pinpoint holes in the nipple).

Physiologic discharge is usually non-spontaneous, which means someone has to elicit the discharge themselves. "Some women describe feeling tenderness behind the nipple that can be relieved by squeezing it," Dr. Fisher said.

Kimberly Sue Stone, MD, a general surgeon specializing in breast surgical oncology with Stanford Health Care, said physiologic discharge is usually clear, milky, green, or brown, and it can stem from a number of causes.

Sometimes, if people recently breastfed but stopped, Dr. Stone said, milk-like fluid can come out with nipple stimulation.

There's another condition called galactorrhea, in which people produce milk when they're not breastfeeding, which could be caused by adrenal problems. (Adrenal glands are located on the kidney and release hormones like cortisol and adrenaline.)

Some medications, Dr. Stone said, can also cause people to create and leak milk even when they're not breastfeeding and haven't recently.

In other people, physiologic breast discharge is just a part of getting older. Lori Fredrick, MD, a breast radiologist at the University of Oklahoma Health Breast Health Network Edmond, said older people can experience dilation in their breast ducts as they age, which can cause the nipples to leak a green or brown fluid.

"It's nothing we worry about, but because it's being held right behind the nipple, it might leak out," Dr. Fredrick said.

Pathologic Nipple Discharge

Pathologic (or abnormal) discharge, on the other hand, may stem from something that's inside the breast. Usually, Dr. Fisher said, medically concerning discharge comes from just one breast or a single duct in that breast. It also tends to be spontaneous, which means it comes out on its own without nipple stimulation. "Patients say they take off the bra at the end of the day and notice fluid in it," Dr. Fisher said.

Usually, Dr. Fisher said, pathologic nipple discharge is clear or bloody; intraductal papillomas, cauliflower-like masses in the breast ducts, are a common cause. Not all papilloma growths are cancerous, but, Dr. Fisher said, about 10 to 15% of them may harbor a malignancy or precancerous cells. According to Dr. Stone, healthcare providers tend to remove papillomas to avoid cancer.

Nipple Discharge and Breast Cancer

Most nipple discharge isn't associated with breast cancer, but clear or bloody nipple discharge can be a symptom of breast cancer in some people, Dr. Fisher said. "It's not necessarily indicative of cancer, but if there is cancer there, it would be bloody or clear, spontaneous, and only in one breast," Dr. Fisher said.

Blood from a cancerous growth in the breast would be bright red, but at other times, Dr. Stone said, the nipples may discharge older, dark brown, or blackish blood. If you're not sure whether your nipple discharge contains blood, your healthcare provider can take a sample of the fluid and examine it under a microscope.

It's worth noting that bloody fluid from the nipple is usually an early symptom—when it is a symptom. "Even if it's breast cancer, if you experience bloody discharge, it's usually early stage and non-life threatening," Dr. Fredrick said.

While bloody discharge should generally prompt people to visit a healthcare provider, it's not always something growing inside the breast. Dr. Fisher said breast ducts can also leak blood after an outside trauma, like an accident or injury.

What To Do if You Have Nipple Discharge

If you have nipple discharge you're concerned about, your healthcare provider can help you determine the cause. Before they order any tests, healthcare providers will ask you whether the discharge is persistent, Dr. Fisher said. If you've only noticed it once or twice, your healthcare provider may tell you to keep an eye on it.

If they're concerned it could be pathologic, they may send you for a breast exam. Breast imaging, like an MRI, can show your provider your breast ducts so they can determine if there's a mass. If there is a mass present in the breast, Dr. Fisher would typically refer a patient to a breast surgeon for further evaluation.

A Quick Review

While the majority of nipple discharge isn't related to anything serious, it's worth visiting your healthcare provider for peace of mind if you're worried. "It's never too soon to talk to a doctor if you're concerned," Dr. Frederick said. "We want to ease your mind and help you understand what's concerning and what's not."

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