Causes

By Mayo Clinic Staff

Nipple discharge is a typical part of how the breast works during pregnancy or breast-feeding. It also can be linked to menstrual hormone changes and common changes in breast tissue, called fibrocystic breast. The milky discharge after breast-feeding most often affects both breasts. It can continue for up to one year or more after giving birth or stopping nursing.

A papilloma is a noncancerous, also called benign, tumor in a milk duct. A papilloma can be linked to bloody discharge. The discharge linked with a papilloma often happens spontaneously and involves a single duct.

The bloody discharge may clear up on its own. But your healthcare professional is likely to want a diagnostic mammogram and a breast ultrasound to see what's causing the discharge.

You also may need a biopsy to confirm that it's a papilloma or to rule out a cancer. If the biopsy shows a papilloma, a member of your healthcare team will refer you to a surgeon to talk about treatment options.

Often, a harmless condition causes nipple discharge. However, the discharge might mean breast cancer, especially if:

  • You have a lump in your breast.
  • The discharge comes from only one breast.
  • The discharge is bloody or clear.
  • The discharge happens on its own and is ongoing.
  • You can see that the discharge is coming from a single duct.

Possible causes of nipple discharge include:

  1. Abscess.
  2. Birth control pills.
  3. Breast cancer
  4. Breast infection.
  5. Ductal carcinoma in situ (DCIS)
  6. Endocrine conditions.
  7. Fibrocystic breasts
  8. Galactorrhea
  9. Hypothyroidism (underactive thyroid)
  10. Injury or trauma to the breast.
  11. Intraductal papilloma.
  12. Mammary duct ectasia
  13. Medicines.
  14. Menstrual cycle hormone changes.
  15. Paget's disease of the breast
  16. Periductal mastitis.
  17. Pregnancy and breast-feeding.
  18. Prolactinoma
  19. Too much handling of the breast or pressure on the breast.

Causes shown here are commonly associated with this symptom. Work with your doctor or other health care professional for an accurate diagnosis.

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Jan. 20, 2024

See also

  1. Amenorrhea
  2. Breast cancer
  3. Breast Cancer
  4. Breast cancer chemoprevention
  5. Breast Cancer Education Tool
  6. Common questions about breast cancer treatment
  7. Infographic: Breast Cancer Risk
  8. Breast cancer staging
  9. Breast cancer types
  10. Dragon Boats and Breast Cancer
  11. Ductal carcinoma in situ (DCIS)
  12. Fibrocystic breasts
  13. Galactorrhea
  14. Genetic Testing for Breast Cancer
  15. Genetic testing for breast cancer: Psychological and social impact
  16. HER2-positive breast cancer: What is it?
  17. Male breast cancer
  18. Mammary duct ectasia
  19. What is breast cancer? An expert explains
  20. Paget's disease of the breast
  21. Paulas story A team approach to battling breast cancer
  22. Pink Sisters
  23. The Long Race Beating Cancer
  24. Weight Loss After Breast Cancer