The discharge can be milky, clear, green, purulent, bloody, or faintly yellow. The consistency can be thick, thin, sticky, or watery. Causes
Nipple discharge can arise from any one or more of the 15 to 20 milk ducts that each breast contains, and its causes can be divided into normal (physiological) and abnormal (pathological). Normal
Milky liquid from nipples is normal during the last few weeks of pregnancy, after childbirth and during breastfeeding. Some newborn babies may leak a milky liquid which is usually normal and lasts a couple of weeks.Stimulation of breasts by massage, using a breast pump or after mammography, may induce yellow, milky, or green nipple discharge in many healthy women of reproductive age. Abnormal
Spontaneous nipple discharge unrelated to pregnancy or lactation is considered abnormal, but mostly have a non-serious cause. Nipple discharge in men is not normal. Discharge from nipples is also more likely to be abnormal (pathological) if it is crystal clear or blood-stained, is from only one breast, or is associated with a breast lump, swelling, redness or overlying skin changes.A blocked or enlarged milk duct can result in nipple discharge.Intraductal papillomas are non-cancerous lesions and commonest in women age 30 to 50. Divided into central and peripheral papillomas, nipple discharge is more frequently observed when they are central. Up to half of women with intraductal papillomas may present with bloody nipple discharge, but it can also be straw-coloured.
They are usually too small to feel and have a rare association with breast cancer.15-20% of people with nipple discharge are found to have duct ectasia. This is usually in perimenopausal and menopausal women, who may have associated pain and retraction of the nipple. A lump may also be present.Ductal carcinoma in situ (DCIS) usually presents with abnormal findings on mammography, but can less frequently present with a lump or nipple discharge in women, whereas in men with DCIS, nipple discharge is the common presentation.Infection in a breast, either mastitis or breast abscess may cause a discharge. Eczema of the nipple may result in a discharge with crusting of the nipple skin.Nipple discharge may be due to breast cancer, particularly if there is an accompanying breast lump. A blood-stained discharge may appear in Pagets disease. Milky
Some condition that cause a raised prolactin can result in a milky liquid appearing from nipples. These include endocrine causes such as pituitary and thyroid disease, and some medications. Such medications include:
Medication for hypertension: Methyldopa, reserpine, verapamil
Gastrointestinal agents: Cimetidine, metoclopramide
Hormones: Estrogen, birth control pill
Opiates: Codeine, heroin, methadone, morphine
Psychotropic drugs: Antipsychotics, monoamine oxidase inhibitors, neuroleptics, selective serotonin reuptake inhibitors, tricyclic antidepressantsSome herbs including anise and fennel have also been implicated as causing leaking of fluid from nipples. Diagnosis
The evaluation of milky nipple discharge in a non-pregnant, not breast feeding women is different to the assessment of other abnormal nipple discharge.