Breast Secretion – Causes of Nipple Discharge

Nipple discharge affects many women who are not pregnant or breastfeeding and the presence of breast secretions do not always indicate any serious problem. While breast milk is expected in pregnancy and after child birth, other secretions from the breast may also occur in women of any age. Young women may experience nipple discharge without any cause for concern but persistent discharge in older women may be a sign of an underlying condition.

Secretions from the breast usually occur from the nipple and nipple discharge should be differentiated from fluids secreted through a breast fistula. A breast or mammary duct fistula is an abnormal passage that forms between a mammary duct in the breast to the surface of the skin, usually near the areola. While a mammary fistula is not very common, it may occur after a prolonged infection and the presence of a fistula should not be considered as nipple discharge. A breast fistula requires further investigation and appropriate treatment.

Types of Nipple Discharge

There are different types of nipple discharge and the type of breast secretion may be an indication of the cause of the discharge.

• Milky discharge may be breast milk production even in women who are not pregnant or breast feeding and is often due to elevated hormonal levels, specifically prolactin.
• Clear discharge and sticky discharge may be a sign of inflammation or infection.
• Bloody discharge may be a sign of severe trauma, infection or cancer.
• Mucus that is yellow or brown and may be mixed with blood could be due to severe infection, especially if accompanied by breast pain.

Evaluating the type of nipple discharge is not usually sufficient to make a conclusive diagnosis. The presence of other signs and symptoms as well as thorough diagnostic investigation by a medical practitioner should determine the underlying cause of the breast discharge.

Signs and Symptoms

Nipple discharge may occur on its own with no other sign or symptoms or may be accompanied by other symptoms which is indicative of certain conditions.

• Nipple discharge may occur from both breasts (bilateral) or one breast (unilateral)
• Breast tenderness, sensitive nipples or breast pain
• Swollen breasts or breast lumps
• Fever
• Irregular menstrual cycle

Causes of Nipple Discharge

In most cases, breast discharge is not a cause for concern but any persistent discharge associated with other changes requires investigation. Any nipple discharge in males needs to be investigated as it is usually an indication of more serious pathology.

Galactorrhea

Galactorrhea is breast milk production in women who are not pregnant or nursing and is often due to elevated prolactin levels (hyperprolactinemia). Hyperprolactinemia may occur as a result of many conditions including :

1. Stimulation of the breasts
2. Pregnancy
3. Stress
4. Injury to the breast
5. Sexual intercourse.
6. Pituitary disorders
7. Thyroid disorders particularly hypothyroidism
8. Kidney or liver failure
9. Certain drugs like oral contraceptives, antidepressants or antihypertensive drugs.

Infections

Breast abscess or breast infection due to bacterial, viral or fungal causes is usually accompanied by breast pain, tenderness, redness of the skin with a white to yellow discharge. A painful breast lump may be felt in the case of an abscess. Infections of the breast are usually one sided and may also cause breast swelling.

Benign Breast Disorders

1. Intraductal papilloma is a small benign tumor of the milk ducts in the breast. It is the most common cause of nipple discharge and usually affects only one breast. The secretion may be bloody or a clear discharge may be noted.
2. Fibrocystic breast disease (FBD) is the most common cause of breast lumps in women, particularly older women. It may affect one or both breasts and the presence of multiple small lumps may be noticed along with breast tenderness.
3. Mammary duct ectasia is the blockage of the milk duct and may affect one breast or both sides. Blockage of the duct often occurs as a result of inflammation due to hormonal changes and may be prone to bacterial infections. Smoking is a predisposing cause for mammary duct ectasia. The nipple discharge in mammary ectasia may vary in color and consistency.

Cancer

Breast cancer, usually intraductal carcinoma, may cause a bloody breast discharge. A breast lump is usually present and swollen lymph nodes (lymphadenopathy) may be noticed.

Hormonal Disorders

Hormonal disorders affecting the female sex hormones which may occur in perimenopause, premature ovarian failure and polycystic ovarian syndrome. Changes in the menstrual cycle are usually evident, with irregular menses, sudden cessation of periods or changes in menstrual flow. Infertility may also accompany these hormonal disorders.

Gynecomastia

Gynecomastia is the enlargement of the male breast which may be normal during puberty. Persistent breast enlargement with tenderness and/or nipple discharge should be investigated although breast secretions in gynecomastia is not common.

Diagnosis of Breast Discharge

While nipple discharge may occur frequently in women who are not pregnant or breastfeeding, persistent breast secretions should be investigated. Persistent breast discharge is of particular concern in women over 40 years of age, where the discharge is from only one breast, bloody discharge with the presence of breast lumps.

After physical examination and a case history, your medical doctor may consider a mammogram, fine needle aspiration and cytology. If the prolactin levels are elevated, further blood tests may be conducted to evaluate the functioning of the thyroid gland, particularly by testing the thyroid stimulating hormone (TSH).

If you are using any hormone replacement therapy or related drugs for menopause, as contraception or for infertility, your medical doctor may discontinue or change the drugs if the breast discharge is severe and accompanied by other symptoms like breast swelling, tenderness or pain.

Women experiencing nipple discharge with a personal or family history of recurrent breast lumps, even benign lumps. should undergo extensive investigation to exclude breast cancer.

References

1. Intraductal Papilloma. Medline Plus
2. Nipple Discharge. Merck
3. Intraductal Carcinoma. National Cancer Institute

Last updated on August 30, 2018.