Nipple Discharge
Fluid from the nipple outside of breastfeeding
Quick Facts
- Type: Symptom (sign)
- Common causes: Hormone changes, ducts, medications
- Reassuring features: Both breasts, multiple ducts, milky or green
- Concerning features: One breast, bloody, with a lump
Overview
Nipple discharge is any fluid that leaks from the nipple. It is completely normal during pregnancy and breastfeeding, but discharge at other times can understandably cause concern. The fluid may be milky, clear, yellow, green, brown, or bloody, and it can come from one or both breasts and from one or several ducts.
Most nipple discharge is caused by benign (non-cancerous) conditions, such as hormonal changes, blocked or widened ducts, or small benign growths. Only a small fraction of cases are linked to breast cancer. The color of the fluid, whether it comes on its own or only when squeezed, and whether it affects one or both breasts all help determine the cause and how urgently it should be evaluated.
Common Causes
Nipple discharge has many possible causes, most of them benign:
- Hormonal changes: Pregnancy, breastfeeding, and the time around the menstrual cycle commonly cause milky or clear discharge.
- Galactorrhea: Milky discharge unrelated to breastfeeding, sometimes from medications, an underactive thyroid, or a small pituitary gland change that raises the hormone prolactin.
- Duct conditions: Widened ducts (duct ectasia) can cause thick green or brown discharge; a small benign growth in a duct (intraductal papilloma) is a common cause of clear or bloody discharge from one duct.
- Infection: An infected breast or abscess may produce pus-like discharge with redness and pain.
- Breast cancer: Less common, but possible, especially with bloody discharge from a single duct in one breast, often with a lump.
Associated Symptoms
Other symptoms alongside the discharge help point to the cause. Note any of these:
- A breast lump or area of thickening
- Skin dimpling, redness, or changes to the nipple's shape
- Breast pain, swelling, warmth, or fever (suggesting infection)
- Missed periods, headaches, or vision changes (which can point to a hormonal cause)
- Discharge that appears on its own versus only when the nipple is squeezed
Discharge that is milky, comes from both breasts and many ducts, and only appears when squeezed is usually benign. Spontaneous, bloody, one-sided discharge from a single duct is more concerning and needs prompt evaluation.
Diagnosis & Evaluation
A clinician will ask about the discharge's color, whether it is spontaneous or expressed, one or both sides, and any related symptoms or medications. The breasts and armpits are examined for lumps. Tests may include:
- Blood tests for prolactin and thyroid function if galactorrhea is suspected
- A pregnancy test when relevant
- Mammography and ultrasound to look at the breast tissue and ducts
- A sample of the fluid or a duct study in some cases
If a pituitary cause of high prolactin is suspected, an MRI of the brain may be arranged.
Treatment & Management
Treatment depends on the cause:
- Benign hormonal discharge: Often needs no treatment beyond reassurance and avoiding squeezing the nipple, which can keep it going.
- Medication-related galactorrhea: May improve if the responsible medicine is changed, with your prescriber's guidance.
- High prolactin: Treated with medication, and sometimes by addressing a thyroid problem or pituitary cause.
- Duct papilloma: The involved duct may be removed surgically, which also confirms the diagnosis.
- Infection: Treated with antibiotics, with drainage of any abscess.
- Cancer: Managed by a specialist team if confirmed.
When to See a Doctor
See a doctor for any nipple discharge that occurs when you are not pregnant or breastfeeding, especially if it:
- Is bloody or clear and comes from a single duct
- Happens on its own without squeezing
- Affects only one breast
- Comes with a lump, skin changes, or nipple changes
- Is milky and you are not breastfeeding, particularly with missed periods, headaches, or vision changes
While most causes are benign, these features deserve prompt assessment so that any serious cause can be found early.
Self-Care & Prevention
Most nipple discharge cannot be prevented, but a few simple steps reduce benign discharge and help you and your doctor sort out the cause:
- Avoid repeatedly squeezing or checking the nipple, which can stimulate the breast and keep discharge going
- Wear a supportive, well-fitting bra and avoid excessive nipple friction or stimulation
- Note the color, which breast and how many ducts are involved, and whether it leaks on its own or only when squeezed
- Tell your doctor about all medicines and supplements, since some can raise prolactin and cause milky discharge
- Keep up with recommended breast screening for your age and risk
Becoming familiar with what is normal for you makes it easier to recognize discharge that needs evaluation, especially spontaneous, bloody, or one-sided discharge.
Frequently Asked Questions
Is nipple discharge usually a sign of cancer?
No. Most nipple discharge comes from benign causes such as hormonal changes, duct conditions, or medications. Bloody or clear discharge from a single duct in one breast, especially with a lump, is more concerning and should be evaluated promptly.
What does the color of nipple discharge mean?
Milky discharge often relates to hormones, green or brown can come from widened ducts, and clear or bloody discharge from one duct is more likely to need investigation. Color is a clue, not a diagnosis, so any unexplained discharge deserves a check.
Why am I leaking milk when I am not pregnant?
Milky discharge outside of breastfeeding is called galactorrhea and is often caused by certain medications, an underactive thyroid, or raised levels of the hormone prolactin. A doctor can order simple blood tests to find the reason.
Will squeezing my nipple make discharge worse?
Yes. Repeatedly squeezing or checking the nipple can stimulate it and keep the discharge going. If you have benign discharge, leaving the nipple alone often helps it settle.
Can men have nipple discharge?
Yes, and in men any nipple discharge, particularly if bloody or one-sided, should always be evaluated, since the threshold for concern is lower than in women.
References
- American Cancer Society. Nipple Discharge.
- Mayo Clinic. Nipple discharge — Symptoms and causes.
- MedlinePlus, U.S. National Library of Medicine. Nipple discharge.
- National Cancer Institute (NCI).