Nipple discharge is an embarrassing condition but more common than many women think.  What exactly is nipple discharge, what causes it and is it anything to worry about?  Read on to learn more.

What is Nipple Discharge?

Nipple discharge is the third most common breast complaint after lumps and breast pain.  A woman’s breasts secrete some fluid throughout most of the adult life.  Nipple discharge is usually nothing to worry about, even though it is inconvenient and bothersome.  

However, nipple discharge may be of concern if it is:

• Bloody or watery with a red, pink, or brown colour.
• Sticky and clear in colour or brown to black in colour.
• Appears spontaneously without squeezing the nipple.
• Persistent.
• On one side only.
• A fluid other than breast milk.

Causes of Nipple Discharge

Milky discharge – discharge that is cloudy, whitish or nearly clear in colour, thin, and non-sticky – is the most common type of nipple discharge.  This discharge is usually caused by lactation or by increased mechanical stimulation of the nipple due to fondling, suckling, or irritation from clothing during exercise or activity.  Drugs or hormones that stimulate the secretion of prolactin can cause the spontaneous, persistent production of milk.  Some pituitary tumours can cause an excess secretion of prolactin that can lead to milky nipple discharge, usually from both breasts.  Opalescent discharge that is green or yellow in colour is normal.

Most bloody or watery discharge is due to a benign condition such as papilloma (a non-cancerous, wart-like tumour) or infection.  Suspicious nipple discharge is due to cancer in about ten percent of cases, meaning that the wide majority of nipple discharges are non-cancerous.

A short list of some of the most common causes of nipple discharge is as follows:

• Mammary Duct Ectasia – one of the most common causes of nipple discharge.  This is where one or more of the ducts beneath the nipples becomes inflamed and clogged with a thick, sticky, green or black substance.
• Intraductal papilloma – a small, usually non-cancerous growth that projects into a milk duct near your nipple.
• Galactorrhea – the nipple discharge associated with this is usually white or clear but can also be yellow or green and can leak from one or both breasts.  It occurs when the body makes too much prolactin – the hormone the brain produces to stimulate milk production after you have a baby.
• Injury – a blunt trauma can cause nipple discharge in both of your breasts.
• Abscess – happens when the nipples become irritated or infected from breastfeeding.
• Fibrocystic changes – result in lumpy, tender breasts, and can produce a clear, yellow, or light green discharge from your nipples.
• Breast cancer – nipple discharge is rarely a sign of breast cancer but it is possible that discharge may indicate that cancer is present within a duct or outside the duct.