Abnormal nipple discharge is abnormal fluid leakage from one or both nipples of the breast.

The likelihood of nipple discharge increases with age and number of pregnancies.

While a milky nipple discharge is rare in men and in women who have never been pregnant, it does occur. When it does, it is likely to be caused by some underlying disease, particularly when accompanied by other changes in the breast(s).

It is relatively common in women who have had at least one pregnancy. A thin yellowish or milky discharge (colostrum) is normal in the final weeks of pregnancy.

The nature of the discharge can range in color, consistency, composition, and may occur on one side or both sides.

"Witch's milk" is a term used to describe nipple discharge in a newborn. The discharge is a temporary response to the increased levels of maternal hormones. Witch's milk should disappear within 2 weeks as hormone levels dissipate in the newborn.

Other nipple discharges can be bloody or purulent (containing pus), depending on the cause.

• A tumor in the brain called a prolactinoma
• A small noncancerous growth in the breast called an intraductal papilloma
• Breast abscess (most commonly seen in women during breastfeeding)
• Breast cancer
• Fibrocystic changes in the breast
• Injury to the breast(s)
• Use of certain drugs including birth control pills, cimetidine, methyldopa, metoclopramide, phenothiazines, reserpine, tricyclic antidepressants, or verapamil
• Widening of the milk ducts called ductal ectasia

Call your health care provider if you have any abnormal nipple discharge.

The doctor will perform a physical exam and ask questions about your medical history and symptoms, including:

• Are you pregnant?
• Are you breastfeeding?
• What color is the drainage?
• Does it look like milk?
• Is is bloody?
• Does it look like pus?
• Is the drainage from both breasts?
• How much drainage is there? For example, does is stain or soak a bra or t-shirt?
• Do you examine your breasts? How often?
• What medications do you take?
• What other symptoms do you have? For example, fever, menstrual cycle changes, a breast lump,breast pain, headaches, or vision changes?

Laboratory tests may be done to check prolactin and thyroid levels and to study the cells in the nipple discharge. Other tests that may be done include:

• Breast biopsy (if a lump is found)
• Head CT scan to look for pituitary tumor
• Mammography
• Transillumination
• Ultrasound of the breast

Galactorrhea. In: Ferri FF. Ferri’s Clinical Advisor 2008: Instant Diagnosis and Treatment. 1st ed. St. Louis, Mo: Mosby; 2008.