Causes of Breast Secretion, 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 of Nipple Discharge

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 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 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.
  • 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.
  • 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 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 is the enlargement of the male breast which may be normal during puberty. Persistent enlargement with breast 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.


  1. Intraductal Papilloma. Medline Plus
  2. Intraductal Carcinoma. National Cancer Institute

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  • cheyenne

    Is it normal for a girl who is 18 to have normal breast discharge?

  • Hi Cheyenne. Yes, it can occur and is often related to menstrual changes and with physical stimulation. However, it is important to exclude causes like pregnancy first. If clear then other possible causes may be investigated. It is advisable that you see a gynecologist and have it assessed further.

  • Aritra Lahiri

    Hi .. I am ari. From last week my nipple has been discharging white liquid. For this reason I facing pain in my breast

  • laila hulu

    Hey,I am 19 years,today in the morning I saw watery and white ingredients is secrets my two breast .I was involve in physical relationship with my bf,so pls suggest about this problem

  • Hi Laila. As you can see from the article above, a breast discharge may not necessarily be a sign of any problem. These discharges can occur with changes in the menstrual cycle and physical stimulation. However, you will also need to consider other possibilities like pregnancy. It is always advisable to seek medical advice so speak to your family doctor. You may need to follow up with a gynecologist.

  • Megan

    Hello. I am 13 years old and last night I felt a lump in my breast. I squeezed it and clear liquid seemed to shoot out of a couple of my Montgomery glands. Once the lump was gone no more liquid came out. Was it like a big sist that I popped? I was on my period if that had to do with anything

  • Hi Megan. It is unlikely that you popped a cyst but it is difficult to say through an online platform. A clear fluid can be secreted from the breasts with homornal changes or physical stimulation. It would be advisable that you speak to a parent and possibly follow up with a doctor just to be sure that there is nothing more to this secretion. Most of the time in your age group it is usually not serious but a doctor will be able to advise you further.

  • Hi Seema. You don’t mention your age or medical history which could be relevant to this discharge so it is difficult to provide a more extensive explanation. Although this minor discharge may not be “abnormal” or anything serious, it may still be worthwhile to consult with your gynecologist. Hopefully you have been going for regular checkups.

  • Seema

    I am 31 yrs..and had delivery before 3 yrs..

  • Hi Seema. We cannot say with any certainty but a minor nipple secretion is not abnormal, especially in a woman who has already had a child. However, given the risk of breast cancer it is always advisable to have it checked up as soon as possible.

  • Nayaab

    I had abortion one month ago.two days ago i notice discharge from my breast and a slight pain.what does it mean?

  • Hi Nayaab. Despite the abortion, the hormonal changes normally associated with pregnancy may have not as yet settled down. This can cause discharge from the breast and tenderness. However, it is advisable that you consult with a gynecologist and have it checked up in the event that it is some other condition.

  • HI Ally. Irrespective of the other symptoms, if the pain is severe and especially if it is worsening then go to the ER immediately. Hopefully you have consulted with a gynecologist by now and if not then see one as soon as possible. This may not be related to your previous breastfeeding and a thorough examination is highly advisable. Your doctor will advise you accordingly.