Nipple Discharge
Fluid that leaks from
one or both nipples is called nipple discharge. Each breast has several (15 to
20) milk ducts. A discharge can come from one or more of these ducts.
Nipple discharge can
occur normally during the last weeks of pregnancy and after childbirth when
breast milk is produced. A nipple discharge can also be caused by breast
stimulation in women who are not pregnant or breastfeeding, especially during
the reproductive years. However, a nipple discharge in men is always abnormal.
A normal nipple
discharge is usually a thin, cloudy, whitish, or almost clear fluid. However,
the discharge may be other colors, such as gray, green, yellow, or brown. A
bloody discharge is abnormal.
Abnormal discharges
vary in appearance depending on the cause. An abnormal discharge may be
accompanied by other abnormalities, such as dimpled skin, swelling, redness,
crusting, sores, and an inverted (retracted) nipple. (A nipple is inverted if
it pulls inward and does not return to its normal position when it is
stimulated.) If a discharge from only one breast occurs on its own (without any
stimulation of the nipple), it is considered abnormal.
Causes of Nipple
Discharge
Several disorders can
cause an abnormal discharge.
A discharge from one
milk duct or from one breast is likely to be caused by a problem with that
breast, such as a noncancerous (benign) tumor or, less commonly, a cancerous
(malignant) breast tumor.
A discharge from both
breasts or from several milk ducts in one breast is more likely to be caused by
a problem outside the breast, such as a hormonal disorder or use of certain
drugs.
Common causes of a
nipple discharge
Usually, the cause is
a benign disorder of the milk ducts, such as the following:
- A benign tumor in a milk duct (intraductal
papilloma)
- Dilated milk ducts (mammary duct ectasia)
- Fibrocystic changes, including pain,
cysts, and general lumpiness
- A breast infection or abscess
Intraductal papilloma
is the most common cause. It is also the most common cause of a bloody nipple
discharge when there is no lump in the breast.
Less common causes of
a nipple discharge
Certain disorders
stimulate the production of breast milk in women who are not pregnant or
breastfeeding In most of these disorders, the level of prolactin (a hormone
that stimulates production of breast milk) is elevated. Taking certain drugs
can have the same effect.
Cancer causes fewer
than 10% of cases.
Warning signs
Nipple discharge is a
cause for concern when it
- Is accompanied by a lump that can be felt
- Is bloody or pink
- Comes from only one breast
- Occurs without the nipple's being squeezed
or stimulated by other means (when it occurs spontaneously)
- Occurs in women aged 40 or older
- Occurs in a boy or man
When to see a doctor
If a nipple discharge
continues for more than one menstrual cycle or if any of the warning signs are
present, women (or men) should see a doctor. Delay of a week or so is not
harmful unless there are signs of infection such as redness, swelling, and/or a
discharge of pus. Women with such symptoms should see a doctor within 1 or 2
days.
What the doctor does
Doctors first ask
questions about the woman's symptoms and medical history. Doctors then do a
physical examination. What they find during the history and physical
examination often suggests a cause of the discharge and the tests that may need
to be done (see Table below).
To help identify the
cause, doctors ask about the discharge and about other symptoms that may
suggest possible causes. They ask
- Whether the discharge comes from one or
both breasts
- What the discharge's color is
- How long it has lasted
- Whether it is spontaneous or occurs only
when the nipple is stimulated
- Whether a lump or breast
pain is present
Women are also asked
whether they have had disorders or take drugs that can increase prolactin
levels.
Doctors examine the
breast, looking for abnormalities, including lumps. If the discharge does
not occur spontaneously, the area around the nipples is gently pressed to try
to stimulate a discharge.
Doctors also feel the
lymph nodes in the armpits and above the collarbone to check for enlarged lymph
nodes.
If doctors suspect
that a hormonal disorder is the cause, blood tests are done to measure the
levels of prolactin and thyroid-stimulating hormone.
If a pituitary or
brain disorder is suspected, magnetic resonance imaging (MRI) or computed
tomography (CT) of the head is done.
If the discharge is
not obviously bloody, it is analyzed to determine whether it contains small
amounts of blood. If blood is present, a sample of the discharge is examined
under a microscope (called cytology) to look for cancer cells.
If a lump can be felt,
ultrasonography or mammography is done. Testing is similar to that
for any breast lump.
Cysts are drained (by
aspiration), and the fluid is tested. If the fluid is bloody, it is checked for
cancer cells.
If lumps are solid,
mammography is done, followed by a biopsy.
When there is no lump
but cancer is still suspected or when other test results are unclear,
mammography is done.
If test results after
aspiration, ultrasonography, or mammography are abnormal, a biopsy is done.
If ultrasonography and
mammography do not identify a cause and the discharge occurs spontaneously and
comes from one milk duct, doctors usually do a special type of mammogram
(called a ductogram, or galactogram). For this procedure, a contrast agent
(which helps make images clearer) is injected into the duct, and images are
taken, just as for a regular mammogram. This test can help rule out or identify
cancer.
If no lump can be felt
and the mammogram is normal, cancer is highly unlikely.
Sometimes a specific
cause cannot be identified.
If women have any of
the following, they should see a doctor who is experienced in managing breast
disorders:
- A lump in the breast
- A bloody or pink discharge
- A spontaneous discharge from one breast
- An abnormality previously detected by
mammography or ultrasonography
Treatment of Nipple Discharge
If a disorder is
identified, it is treated.
If a noncancerous
tumor or disorder is causing a discharge from one breast, the duct that the
discharge is coming from may be removed. This procedure requires only a local
anesthetic and does not require an overnight stay in the hospital.
Key Points
- Usually, the cause of nipple discharge is not cancer.
- If the discharge comes from both breasts or from several milk ducts and is not bloody or pink, the cause is usually a noncancerous hormonal disorder.
- If the discharge comes from only one breast and is bloody or pink, cancer is possible, especially in women aged 40 or older.
- Whether blood tests, imaging (such as ultrasonography), or both, are done depends on the suspected cause.