Nipple Discharge

Is nipple discharge normal?

Each nipple has about 15 to 20 milk duct openings. Small amounts of fluid are produced in the ducts throughout adult life. Most women can express a little fluid if they squeeze, which is why doctors advise against repeatedly checking by squeezing: stimulation produces more discharge.

Doctors sort discharge into two groups:

Nipple discharge by color

• Milky white: galactorrhea from raised prolactin, medicines, nipple stimulation, or recent pregnancy or breastfeeding.
• Green, gray, black or brown and sticky: usually duct ectasia or fibrocystic changes.
• Yellow or pus-like: infection such as mastitis or a breast abscess.
• Clear and watery: needs evaluation if one-sided and spontaneous.
• Bloody or pink: most often an intraductal papilloma, but needs imaging to exclude cancer.

Color alone does not diagnose the cause, but it guides which tests are needed.

Common causes

Intraductal papilloma

A small, benign wart-like growth in a duct just behind the nipple, the most common cause of bloody discharge from one duct. It may be felt as a small lump near the areola. It is usually removed to confirm it is benign.

Duct ectasia

Ducts under the nipple widen and thicken with age, usually around menopause, and fill with sticky, thick, green or black fluid. The nipple can become drawn in (slit-like inversion). It can cause tenderness and inflammation (periductal mastitis), especially in smokers.

Fibrocystic breast changes

Lumpy, tender breasts that vary with the menstrual cycle, sometimes with green, brown or yellow discharge from both sides.

Infection

Mastitis and breast abscesses cause pus-like discharge with pain, redness, warmth and fever. Outside breastfeeding, infection is often linked to smoking and duct ectasia.

Galactorrhea (milky discharge)

Galactorrhea is milky discharge in someone not pregnant or breastfeeding. Causes include:

• Medicines: antipsychotics (risperidone, haloperidol), metoclopramide, some antidepressants, opioids, verapamil, estrogen
• Prolactinoma: a benign pituitary tumor making prolactin, often with missed periods, low libido, headaches or vision changes
• Hypothyroidism
• Chronic kidney disease
• Nipple or chest wall stimulation, including tight clothing, frequent breast checks, piercings and shingles
• Recent pregnancy, miscarriage or breastfeeding

Cancer

Breast cancer is found in roughly 5 to 15% of people who have pathologic discharge evaluated, and much less often with physiologic discharge. The risk is higher with bloody discharge, an associated lump, age over 50, and in men. Paget's disease of the nipple causes a red, scaly, crusting rash on the nipple that may ooze. Ductal carcinoma in situ (DCIS) can present with discharge alone.

Nipple discharge in men

Nipple discharge in men is uncommon and more often linked to cancer than in women, so it always needs evaluation. Milky discharge in men suggests high prolactin.

How doctors evaluate nipple discharge

1. History: color, one or both sides, spontaneous or expressed, medicines, menstrual history, pregnancy, headaches and vision.
2. Breast exam: looking for a lump and identifying which duct the fluid comes from.
3. Imaging: a diagnostic mammogram and ultrasound for pathologic discharge (ultrasound first under age 30). MRI is used if these are normal but suspicion remains.
4. Blood tests for milky discharge: pregnancy test, prolactin, thyroid function and kidney function. A pituitary MRI if prolactin is high without another cause.
5. Ductography (galactogram): dye injected into the duct to show a papilloma, now used less often.
6. Biopsy or duct excision: to diagnose a lesion or stop persistent discharge.

Treatment

• Physiologic discharge: no treatment. Stop squeezing the nipples and wear a supportive bra. It usually settles within weeks to months.
• Medicine-related galactorrhea: your doctor may change the medicine. Do not stop antipsychotics without advice.
• Prolactinoma or high prolactin: dopamine agonist medicines such as cabergoline usually shrink the tumor and stop discharge.
• Hypothyroidism: thyroid hormone replacement.
• Infection: antibiotics, and drainage of an abscess.
• Papilloma or persistent single-duct discharge: surgical removal of the affected duct (microdochectomy) or central ducts.
• Cancer: treated according to type and stage.

Frequently asked questions

Is nipple discharge a sign of breast cancer?

Usually not. Most nipple discharge is caused by benign conditions such as duct ectasia, papillomas, fibrocystic changes or high prolactin. Discharge is more concerning if it is bloody or clear, from one breast and one duct, comes out on its own, or comes with a lump. These need imaging.

Why do I have milky discharge when I'm not pregnant?

Milky discharge, called galactorrhea, is often caused by raised prolactin from medicines, a benign pituitary tumor, an underactive thyroid, or frequent nipple stimulation. It can also persist for months to years after breastfeeding. A pregnancy test and prolactin blood test are the first steps.

Is it normal to have discharge when squeezing the nipple?

Yes. Many women can express a small amount of milky, green, yellow or gray fluid from several ducts in both breasts. This is generally normal. Avoid repeated squeezing, which stimulates more discharge. See a doctor if discharge is bloody, clear, one-sided or comes out on its own.

What does green nipple discharge mean?

Green, sticky discharge from several ducts is usually caused by duct ectasia or fibrocystic breast changes. It is very rarely linked to cancer. If it comes with pain, redness or a lump, or is from one duct only, see a doctor.

Can men have nipple discharge?

Yes, but it is uncommon. In men, milky discharge often points to high prolactin, and bloody discharge needs prompt investigation for breast cancer. Any nipple discharge in a man should be checked by a doctor, usually with ultrasound and mammography.