Nipple discharge is a common complaint in women who are not pregnant or breastfeeding, especially during the reproductive years. Nipple discharge is not necessarily abnormal, even among postmenopausal women, although it is always abnormal in men. Spontaneous unilateral nipple discharge, regardless of color, is considered abnormal.
Nipple discharge can be serous (yellow), mucinous (clear and watery), milky, sanguineous (bloody), purulent, multicolored and sticky, or serosanguineous (pink). It may occur spontaneously or only in response to breast manipulation.
Pathophysiology of Nipple Discharge
Nipple discharge may be breast milk or an exudate produced by a number of conditions.
Breast milk production in nonpregnant and nonlactating women (galactorrhea Prolactinoma Prolactinomas are noncancerous tumors made up from lactotrophs in the pituitary gland. The most common symptom of a prolactinoma is galactorrhea. Diagnosis is by measurement of prolactin levels... read more ) typically involves an elevated level of prolactin, which stimulates glandular tissue of the breast. However, only some patients with elevated prolactin levels develop galactorrhea.
Etiology of Nipple Discharge
Most frequently, nipple discharge has a benign cause (see table Some Causes of Nipple Discharge Some Causes of Nipple Discharge 
). Cancer (usually intraductal carcinoma or invasive ductal carcinoma) causes < 10% of cases. The rest result from benign ductal disorders (eg, intraductal papilloma, mammary duct ectasia, fibrocystic changes Etiology 
), endocrine disorders (eg, pituitary tumor), liver disorders, breast abscesses or infections, or use of certain drugs. Of these causes, intraductal papilloma is probably the most common; it is also the most common cause of a bloody nipple discharge without a breast mass.
Evaluation of Nipple Discharge
History
History of present illness should include the following:
Whether the current discharge is unilateral or bilateral
What its color is and whether it is bloody or blood-tinged
How long it has lasted
Whether it is spontaneous or occurs only with nipple stimulation
Whether a mass Breast Masses (Breast Lumps) The term breast mass (lump) may be discovered by patients incidentally or during breast self-examination or by the clinician during routine physical examination. Masses may be painless or painful... read more
or breast pain Mastalgia (Breast Pain) Mastalgia (breast pain) is common and can be localized or diffuse and unilateral or bilateral. Localized breast pain is usually caused by a focal disorder that causes a mass, such as a breast... read more is present
Review of systems should seek symptoms suggesting possible causes, including the following:
Amenorrhea, infertility, headache, or visual disturbances: Pituitary tumor Pituitary Lesions Patients with hypothalamic-pituitary lesions generally present with some combination of Symptoms and signs of a mass lesion: headaches, altered appetite, thirst, visual field defects—particularly... read more
Ascites Ascites Ascites is free fluid in the peritoneal cavity. The most common cause is portal hypertension. Symptoms usually result from abdominal distention. Diagnosis is based on physical examination and... read more or jaundice Jaundice Jaundice is a yellowish discoloration of the skin and mucous membranes caused by hyperbilirubinemia. Jaundice becomes visible when the bilirubin level is about 2 to 3 mg/dL (34 to 51 micromol/L)... read more
: Liver disorders
Nonlactational mastitis may be periductal mastitis, idiopathic granulomatous mastitis, or tuberculous mastitis.
Past medical history should include possible causes of hyperprolactinemia, including chronic renal failure, pregnancy, liver disorders, and thyroid disorders, as well as history of infertility, hypertension, depression, breastfeeding, menstrual patterns, and cancer. Clinicians should ask specifically about drugs that can cause prolactin release such as oral contraceptives, antihypertensive drugs (eg, methyldopa, reserpine, verapamil), H2-antagonists (eg, cimetidine, ranitidine), opioids, and dopamine D2 antagonists (eg, many psychoactive drugs, including phenothiazines and tricyclic antidepressants).
Physical examination
Physical examination focuses on the breast examination Evaluation Breast symptoms (eg, masses, nipple discharge, pain) are common, accounting for > 15 million physician visits/year. Although > 90% of symptoms have benign causes, breast cancer is always... read more 
. In male patients, gynecomastia, if present, is noted. The breasts are inspected for symmetry, dimpling of the skin, erythema, swelling, color changes in the nipple and skin, and crusting, ulceration, or retraction of the nipple. The breasts are palpated for masses and evidence of lymphadenopathy in the axillary or supraclavicular region. If there is no spontaneous discharge, the area around the nipples is systematically palpated to try to stimulate a discharge and to identify any particular location associated with the discharge.
A bright light and magnifying lens can help assess whether the nipple discharge is uniductal or multiductal.
Red flags
Certain findings are of particular concern:
Bloody discharge
Unilateral discharge
Spontaneous discharge
Age ≥ 40
Male sex
Interpretation of findings
If a mass is present or discharge is guaiac-positive, even if bilateral, cancer must be considered.
Discharge that is bilateral and/or multiductal and guaiac-negative suggests an endocrine cause.
Presence of any of the following requires follow-up with a surgeon who is experienced with breast disorders:
A breast mass
A bloody (or guaiac-positive) discharge
A spontaneous unilateral discharge
History of an abnormality on a mammogram or a breast ultrasound
For other suggestive findings, see table Some Causes of Nipple Discharge Some Causes of Nipple Discharge .
Testing
If endocrine causes are suspected, the following are measured:
Prolactin level
Thyroid-stimulating hormone (TSH) level
If discharge is guaiac-positive, the following is done:
Cytology
If there is a palpable breast mass, evaluation may include
Ultrasonography, cyst aspiration, or mammography
If there is no mass but cancer is otherwise suspected or if other tests are indeterminate, the following is done:
Mammography
If results of imaging or cytology (of cyst aspirate) are abnormal, image-guided biopsy is done.
If mammography and ultrasonography do not identify a source and the discharge is spontaneous and comes from a single duct or breast, evaluation may include
Ductography (contrast-enhanced imaging of the milk duct) or image-guided biopsy
Treatment of Nipple Discharge
Treatment of a nipple discharge is based on the cause. If imaging identifies a lesion, core needle biopsy is done.
Breast cancer is treated as appropriate.
Intraductal papillomas, which are the most common cause of bloody nipple discharge, are usually excised after diagnosis with needle biopsy. This procedure prevents further nipple discharge and rules out the small possibility of a coexisting cancer. Exceptions to this are microscopic, incidentally discovered papillomas detected during biopsy of calcifications.
Hyperprolactinemia is treated with drugs or surgical removal of a pituitary tumor. Liver disorders are treated as appropriate for the specific disorder.
Key Points
Nipple discharge is most often benign.
Bilateral, multiductal, guaiac-negative discharge is usually benign and has an endocrine etiology.
Spontaneous, unilateral discharge requires diagnostic testing; this type of discharge may be cancer, particularly if it is bloody (or guaiac-positive).
Presence of a breast mass, a bloody (or guaiac-positive) discharge, or history of an abnormality on a mammogram or an ultrasound scan requires follow-up with a surgeon who is experienced with breast disorders.
Drugs Mentioned In This Article
| Drug Name | Select Trade |
|---|---|
methyldopa |
Aldomet |
verapamil |
Calan, Calan SR, Covera-HS, Isoptin, Isoptin SR, Verelan, Verelan PM |
cimetidine |
Acid Reducer, Major Acid Reducer, Tagamet, Tagamet HB |
ranitidine |
Acid Reducer, Ranitidine, Taladine, Zantac, Zantac EFFERdose, Zantac Maximum Strength, Zantac Solution, Zantac Syrup |
dopamine |
Intropin |
