It is normal for nipples to pass a little fluid if they are squeezed, even in women who are not lactating. Pressure on the nipples – from forceful sucking and also squeezing – sends a signal to the brain to release prolactin, a hormone produced by the pituitary gland. Prolactin triggers the secretion of fluid from the breasts.

On the other hand, spontaneous discharge from the nipples occurs in only about five percent of women. The fluid produced may range in color from clear to white to gray to green; it may be watery or have a sticky consistency similar to egg whites. Spontaneous breast discharges are usually due to increased levels of prolactin, which is more likely to occur around puberty and perimenopause. It may also result from a variety of factors. Certain drugs such as birth control pills, antihypertensives, and tranquilizers – or underlying conditions, such as hyperparathyroidism or a pituitary tumor – can increase the secretion of prolactin.

A discharge from both nipples usually signals a benign condition. However, one that involves only one nipple deserves closer examination by your doctor. It may be caused by several intraductal papillomas (see below) and will stop when they are removed, but it can also be a sign of a precancerous or cancerous condition. When nipple discharge is bloody, evaluation is needed. Your physician will examine your discharge to distinguish if the secretions are from a benign (noncancerous) or malignant (cancerous) problem.

Inverted nipple: Most women have everted (outward protruding) nipples. But many women, starting at puberty, have inverted (inward tucked) nipples and this is considered to be normal. One or both nipples may be inverted. Thus, it can be a normal anatomical condition to have inverted nipples since development; however, after puberty, it is abnormal to experience a change in the shape and form of the nipple.

Inflammatory conditions of the breast, such as ductal ectasia (see below), infection, or abscess, can cause a change in the shape or form of the nipple. Although nipple inversion can be a symptom of breast cancer, it can also be totally benign. For an inverted nipple, you should see a breast specialist and have a clinical breast exam as well as a mammogram (and possibly an ultrasound) of the area behind the nipple.

Ectasia

This condition usually affects women who are going through perimenopause or who are smokers. The mammary ducts, which are located under the nipple, become dilated (widened), thin walled, and accumulate secretions. This normal process of dilation of the milk gland is called ectasia.

In some cases, ectasia can lead to a blockage of the ducts. As a result, fluid may become pooled and leak into the surrounding tissue, causing infection, chronic inflammation, or abscesses. If these types of infections (also referred to as periductal mastitis) occur, it may cause scar tissue to develop, thus drawing the nipple inward. In addition, this infection may cause breast pain and thick, sticky, gray-to-green, nipple discharge.

Care: Treatment for ectasia generally involves evaluation by your healthcare provider for treatment of symptoms. This may include warm compresses or antibiotics. In some cases, surgery is required to remove the breast duct or ducts that are causing the problem.

Intraductal papilloma

An intraductal papilloma is a small, wart-like growth that projects into the breast ducts near the nipple. This causes a bloody or sticky discharge. In addition, any slight bump or bruise near the nipple can cause the papilloma to bleed.

While single papillomas most often affect women nearing menopause, multiple intraductal papillomas – which often occur in both breasts – are more common in younger women. Multiple intraductal papillomas are more likely to be associated with a lump than with nipple discharge.

Care: If the discharge becomes bothersome, the duct can be surgically removed, often without changing the appearance of the breast. Any papilloma associated with a lump is surgically removed.

If there is a lump with the discharge, this will be of primary concern to your physician. Keep in mind, however, that in breastfeeding women, lactational mastitis complicated by an abscess can often cause a lump beneath the areola, as well as a discharge.

A milky discharge from both nipples, when it is not related to breastfeeding, is called galactorrhea. This is usually due to an increase in the hormone prolactin, which produces milk. Galactorrhea may be caused by tranquilizers, marijuana, or high doses of estrogen and is often accompanied by an absence of menstrual periods.

Care: Nipple discharges that are a result of a benign breast condition may be treated by keeping the nipple clean, among other treatments. Nipple discharges that are a result of infections may require antibiotics or hospitalization.