One of the most obvious explanations for fluid leaking from the nipple is that you're pregnant or currently breastfeeding.
Nipple discharge may also be caused by a wide range of conditions, most of which are harmless or easily treated.
If you are unsure of the cause of your breast discharge or you're embarrassed or worried, see your doctor, especially if the discharge is bloodstained or only comes from one breast.
If the discharge is milky and comes from both nipples, the most likely explanation is that you're pregnant.
In pregnancy, the breasts may start to produce milk from as early as the second trimester (weeks 14-26), and some women continue to produce milk up to two years after stopping breastfeeding.
If you think you may be pregnant, see your doctor or pharmacist for a pregnancy test. You can also read our article on [Am I pregnant?]
If pregnancy has been ruled out it's likely that your nipple discharge is caused by one of the following conditions:
These conditions are explained in more detail below, to give you a better idea of whether you may be affected. However, it's important to see your doctor for a professional diagnosis and treatment.
If the discharge is bloodstained and from a single breast, the cause is likely to be duct papilloma.
A papilloma is a harmless wart-like growth, usually about 1-2cm in size, found inside one of the breast ducts. The breast ducts carry milk from the gland to the nipple (see diagram). The papilloma is usually just behind the nipple and can cause fluid or blood to seep out of the nipple.
You'll usually just have one papilloma, which means it can be easily removed.
Although the discharge may be alarming, rest assured that papilloma is not cancer, and is not likely to turn into cancer. However, you should still get it checked by your doctor, so they can rule out breast cancer and offer you any necessary treatment.
If the discharge is brown, green or cheesy, it's likely you have a harmless condition called duct ectasia.
Duct ectasia tends to affect women approaching the menopause. As the breasts age, the milk ducts behind the nipple get shorter and wider and may produce a discharge. This is a normal, age-related change and nothing to worry about.
A lump can sometimes be felt behind the nipple, which is just scar tissue, and the nipple sometimes becomes inverted.
Even though this condition is harmless and tends to clear up without treatment, it's important that you see your doctor so they can rule out breast cancer. Don't worry, having duct ectasia does not increase your risk of developing breast cancer in the future.
If the discharge contains pus, the cause will probably be a breast abscess or abscess around the nipple.
An abscess is a painful collection of pus that usually forms under the skin after a bacterial infection. The surrounding skin may also be red, warm and swollen.
A breast abscess is usually a complication of mastitis (inflammation of the breast). If you have been to see your doctor because of mastitis, you may already have been given antibiotics. If, after taking antibiotics, your breast is still hard, red and painful, your doctor may refer you to a specialist breast unit to confirm the diagnosis of a breast abscess.
Less common causes of nipple discharge are:
Your doctor should refer you to a specialist for further investigation if:
Breast cancer is an unlikely cause, but needs to be ruled out, especially if:
Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.