Causes

Nipple discharge is a normal part of breast function during pregnancy or breast-feeding. It may also be associated with menstrual hormone changes and fibrocystic changes. The milky discharge after breast-feeding will normally affect both breasts and can continue for up to two or three years after stopping nursing.

A papilloma is a noncancerous (benign) tumor that can be associated with bloody discharge. The discharge associated with a papilloma often occurs spontaneously and involves a single duct. Although the bloody discharge may resolve on its own, your doctor will likely recommend a diagnostic mammogram and a breast ultrasound to see what's causing the discharge. You may also need a biopsy to confirm that it's a papilloma or to exclude a cancer. If the biopsy confirms a papilloma, your doctor will refer you to a surgeon to discuss treatment options.

Often, nipple discharge stems from a benign condition. However, breast cancer is a possibility, especially if:

• You have a lump in your breast
• Only one breast is affected
• The discharge contains blood or is clear
• The discharge is spontaneous and persistent
• The discharge affects only a single duct

Possible causes of nipple discharge include:

• Abscess
• Birth control pills
• Breast cancer
• Breast infection
• Ductal carcinoma in situ (DCIS)
• Endocrine disorders
• Excessive breast stimulation
• Fibrocystic breasts (lumpy or rope-like breast tissue)
• Galactorrhea
• Injury or trauma to the breast
• Intraductal papilloma (a benign, wartlike growth in a milk duct)
• Mammary duct ectasia
• Medication use
• Menstrual cycle hormone changes
• Paget's disease of the breast
• Periductal mastitis
• Pregnancy and breast-feeding
• Prolactinoma