Mammary duct ectasia

Date Updated: 09/05/2025

Overview

Mammary duct ectasia (ek-TAY-zhuh) is a noncancerous breast condition that affects the tubes that carry milk, called the milk ducts. It happens when one or more milk ducts beneath your nipple widen, thicken and fill with fluid. This can cause the milk ducts to become blocked or clogged with a thick, sticky substance that often is yellow or green in color.

Mammary duct ectasia often has no symptoms. But some people may have:

Nipple discharge.
Breast tenderness.
Inflammation of the clogged duct, which is called periductal mastitis.

Mammary duct ectasia most often happens during perimenopause, around age 45 to 55. But it also can happen after menopause. The condition often gets better without treatment. If symptoms don't go away, you may need antibiotics or possibly surgery to remove the clogged milk duct.

Although changes in your breasts may seem concerning, mammary duct ectasia and periductal mastitis aren't risk factors for breast cancer. It's a good idea to talk with your healthcare professional about any changes in your breasts.

Symptoms

Mammary duct ectasia often doesn't cause any symptoms. People with symptoms may have:

A dirty white, yellow, green or black nipple discharge from one or both nipples.
Tender breasts or nipples.
A change in color of the nipple and surrounding skin, called the areola. This change may be a shade of red, purple or brown, depending on your skin color.
A breast lump or thickness near the clogged duct.
A nipple that's turned inward, also called inverted.

Sometimes, a blocked milk duct gets infected. This is called mastitis. Mastitis can cause breast tenderness, inflammation in the areola and fever.

Symptoms of mammary duct ectasia may get better on their own.

When to see a doctor

Make an appointment with your healthcare professional if you notice changes in your breasts that don't go away or that worry you. Some things to watch for are a new breast lump, sudden nipple discharge, a change in skin color, skin swelling or irritation, or an inverted nipple.

Causes

Experts don't know exactly what causes mammary duct ectasia. The condition may be related to changes in the breast tissue. Your breasts are made up of connective tissues that have tiny tubes inside called milk ducts that carry milk to your nipple. Mammary duct ectasia happens when a milk duct beneath the nipple widens, which often happens with age. The duct walls may thicken and fill with fluid, becoming blocked or clogged with a sticky substance. This can cause painful swelling, called inflammation.

Risk factors

Although the exact cause of mammary duct ectasia isn't known, certain risk factors do exist. They include:

Age. Mammary duct ectasia is more common in perimenopause or menopause. As you age, your breast tissue changes. Your breasts become replaced with fat instead of the ducts and glands that make milk. This is called involution. These breast changes can sometimes cause a milk duct to get blocked, which can lead to inflammation that comes with mammary duct ectasia.
Smoking. Cigarette smoking increases your risk of mammary duct ectasia. Smoking may make it more likely that your milk ducts will widen. This can lead to inflammation and, possibly, mammary duct ectasia.
Nipple inversion. A nipple that suddenly turns inward may block the flow of milk and cause inflammation and infection. It also may be a sign of a more serious underlying condition — such as cancer — if you also have a breast lump.

Complications

Usually, the complications of mammary duct ectasia aren't serious, but they can be bothersome. They may include:

Nipple discharge. Nipple discharge caused by mammary duct ectasia can be frustrating. Fluid leaking from your nipples can cause embarrassing wetness and stains on your clothes.
Breast pain. Mammary duct ectasia can cause swelling and tenderness around your nipples.
Infection. An infection may develop in the clogged milk duct. This can cause pain in or around the nipple, a sick feeling, or a fever. Lasting skin color changes and pain that's getting worse could be symptoms of a bacterial infection. A bacterial infection may lead to a collection of pus in your breast tissue. This is called an abscess. A procedure may be needed to drain the abscess.
Concern about breast cancer. When you notice a change in your breast, you may worry that it's a sign of breast cancer. This may be especially true if you have a hard lump around the nipple or areola. Having mammary duct ectasia doesn't increase your risk of breast cancer. Still, it's important to see your healthcare professional soon anytime you notice breast changes.

Diagnosis

Mammary duct ectasia may be diagnosed based on information you give to your healthcare professional and the results of a physical exam. You also might need additional tests, such as:

Ultrasound of the nipple and areola. An ultrasound uses sound waves to make images of breast tissue. It allows your healthcare professional to look at the milk ducts beneath your nipple.
Mammogram. A mammogram is an X-ray of your breast. It can help your healthcare professional look at your breast tissue. If a closer look is needed, your healthcare professional may use a diagnostic mammogram. This gives more-detailed views of a specific area of your breast than a screening mammogram does.
Magnetic resonance imaging, also called MRI. MRI uses a magnetic field and radio waves to create pictures of the inside of the breast. This imaging may be used if other tests don't give your healthcare professional enough information.
Biopsy. If you have a lump in your breast, your healthcare professional may recommend a biopsy. A biopsy is a procedure to remove a sample of tissue for testing in a lab. This is done by inserting a needle through the skin and into the breast tissue. The tissue is sent to a lab and looked at under a microscope. This test can tell if the cells from the sample are cancerous.

Treatment

Mammary duct ectasia doesn't always require treatment. But if you have symptoms that bother you, treatment options may include:

Antibiotics. Your healthcare professional may prescribe an antibiotic for 10 to 14 days to treat an infection caused by mammary duct ectasia. Even if your symptoms get better or go away after starting the antibiotic, it's important to take all your medicine as prescribed.
Pain medicine. You could try a mild pain reliever, such as acetaminophen (Tylenol, others) or ibuprofen (Advil, Motrin IB, others), as needed for breast pain. Follow your healthcare professional's recommendation on which pain reliever is best for you.
Surgery. If an abscess forms and antibiotics don't work, surgery might be needed to remove the clogged milk duct. This is done through a tiny cut made near the nipple. Surgery is usually not needed for mammary duct ectasia.

Self care

To relieve pain caused by mammary duct ectasia, you might try these self-care measures:

Use warm compresses. A warm compress placed on your breast may soothe pain.
Use breast pads for nipple discharge. Using breast pads or nursing pads can keep fluid from leaking through your clothing. These pads are available at drugstores and many retail stores that sell baby care products.
Wear a support bra. Choose bras with good support to minimize breast pain. A well-fitting bra also can help keep a breast pad in place to absorb nipple discharge.
Sleep on the opposite side. Avoid sleeping on the side of your body with the affected breast. This can help prevent swelling and further discomfort.
Stop smoking. Smoking may make it harder to treat an infection. Ongoing smoking may cause infections to come back or an abscess.
Try not to squeeze or touch your nipples. Care for you nipples gently. Avoid squeezing, rubbing or touching them often. This can cause nipple discharge that doesn't stop.

Preparing for your appointment

If you notice a new lump in your breast or any other changes, you'll likely see a member of your primary healthcare team first. Sometimes, based on a breast exam or the results of a mammogram or ultrasound, you may be referred to a breast health specialist.

What you can do

The first appointment focuses on your medical history and the symptoms you're having, including how they're related to your menstrual cycle. To prepare for this discussion with your healthcare professional:

Write down all your symptoms, even if they seem unrelated to the appointment.
Review key personal information, including major stresses or recent life changes.
Make a list of all medicines, vitamins and supplements that you regularly take.
Write down questions you have, to make sure you remember everything you want to ask.

For mammary duct ectasia, here are some questions you might ask your healthcare professional:

What's causing my symptoms?
Will this condition get better on its own, or will I need treatment?
What are my treatment options?
Is there an over-the-counter medicine I can take for pain relief?
What other things can I do to take care of myself?
Do you have printed information I can take home with me? What websites do you recommend?

What to expect from your doctor

Your healthcare professional may ask you several questions, such as:

How long have you had symptoms?
Have your symptoms changed over time?
Do you have breast pain? How bad is it?
Do you have nipple discharge? How would you describe the color, texture and amount?
Do you have symptoms in one or both breasts?
Have you had a fever?
When was your last mammogram?
Have you ever been diagnosed with a precancerous breast condition?
Have you ever had a breast biopsy or been diagnosed with a breast condition that was not cancer?
Has anyone in your family had breast cancer?
What, if anything, helps your symptoms?
What, if anything, makes your symptoms worse?