Overview and Causes of Nipple Discharge

Overview

Nipple discharge is a symptom in which milk comes out of the nipple when the nipple is pressed or pulled, or when the breast is compressed. It can occur in both men and women, but it is not common in men. Nipple discharge is the third most common symptom reported by patients who visit a hospital for breast-related problems. Most nipple discharge is caused by physiological reasons, but it can also be a symptom of a condition that requires treatment, so it is necessary to differentiate the underlying cause.

Causes

The causes of nipple discharge can be broadly divided into physiological factors, medication-related factors, and diseases.

(1) Physiological factors Nipple discharge can occur normally during pregnancy, after childbirth, or while breastfeeding. Nipple discharge may continue for up to one year after breastfeeding is stopped, and this is normal. It can also occur due to hormonal changes, and it may also occur when the nipples are stimulated or the breasts are compressed.

(2) Medications that can cause nipple discharge Nipple discharge can also occur in patients taking medications such as psychiatric drugs, including antidepressants (serotonin reuptake inhibitors, imipramine, phenothiazines, butyrophenones, sulpiride, risperidone, reserpine, etc.), gastrointestinal medications (metoclopramide, domperidone, H2 receptor antagonists), antihypertensive medications (methyldopa, calcium channel blockers), oral contraceptives, and hormone medications (estrogen, antiandrogens). Nipple discharge may also occur from drinking herbal teas or health foods made with herbs such as nettle, fennel, thistle, anise, and fenugreek seeds, or due to narcotics (marijuana, opiates).

(3) Diseases that cause nipple discharge If milk is discharged regardless of pregnancy or childbirth, a disease in which the pituitary hormone that promotes milk secretion (prolactin) is overproduced and secreted should be suspected. Prolactin may be overproduced and secreted due to brain tumors such as prolactinomas and pituitary adenomas. Blood prolactin levels can also rise, causing nipple discharge, due to systemic diseases such as chronic kidney failure with persistent kidney dysfunction, hypothyroidism, Cushing syndrome, and cirrhosis. Among breast diseases, common causes are intraductal papilloma, ductal ectasia, breast cancer, and infection, in that order. Intraductal papilloma is a benign tumor in the breast and may discharge blood as well. Mastitis, in which pus-tinged discharge is expelled through the nipple due to a duct infection, often occurs during breastfeeding.

So far, we have explained nipple discharge. In the next part, we will look at the symptoms and treatment of nipple discharge.

Source: Korea Disease Control and Prevention Agency, National Health Information Portal