Nipple Discharge in Men: Causes and When to Worry

Nipple discharge in men is not normal, and it always deserves a proper examination. Most of the time the cause turns out to be benign: a hormone problem, a medication, or irritation of the milk ducts that every man still has behind the nipple. A small number of cases are caused by breast cancer, and the only way to know which group you fall into is to be examined.

I am Dr. Babak Moeinolmolki, and I see men every week who are worried about something behind the nipple. Discharge is less common than a lump or tenderness, but it tends to frighten people more. This article explains what the different types of discharge usually mean, how the workup is done, and where gynecomastia fits in.

Is nipple discharge in men normal?

Nipple discharge in men is never considered normal. Men have a small amount of breast tissue and a few rudimentary milk ducts behind each nipple, and those ducts should stay dry. Any fluid that leaks on its own or appears when the nipple is squeezed should be examined by a physician, even when it is clear and painless.

The NIH StatPearls review of nipple discharge states this plainly: in women, some discharge can be physiologic, but in men it is always abnormal and should prompt an evaluation. That does not mean it is dangerous. It means the reason has to be found.

Men often find discharge by accident. A spot of fluid on a shirt, a crust on the nipple in the morning, or a drop of fluid after squeezing a sore nipple. Squeezing repeatedly to check can itself irritate the ducts and keep the fluid coming, so the first practical advice is to stop checking and book an exam.

What causes nipple discharge in men?

Nipple discharge in men is caused by hormonal problems that raise prolactin, medications that block dopamine, hypothyroidism, chronic kidney or liver disease, benign duct conditions such as papilloma or duct ectasia, infection, chest trauma or repeated nipple stimulation, and in a minority of cases breast cancer. The type of fluid points toward the likely group.

It helps to sort the causes into two groups, because the workup follows directly from which group you seem to be in.

The first group is systemic. Something in the body raises the hormone prolactin, and prolactin tells breast tissue to make milk. In men this produces a milky fluid, usually from both nipples and from several ducts at once, and it often comes with low libido, erectile difficulty, or new breast tissue. A benign pituitary tumor called a prolactinoma is the classic cause. Our article on prolactin and gynecomastia covers that hormone in detail. An underactive thyroid can do the same thing, which is one reason we check thyroid function in every man with discharge (see thyroid and gynecomastia). Kidney and liver disease interfere with how hormones are cleared and can produce it as well.

Medications belong in this group too. Drugs that block dopamine allow prolactin to rise. Antipsychotics are the best known, but some antidepressants, certain blood pressure medicines, opioids, and anti-nausea drugs such as metoclopramide can contribute. Many of the same drugs appear on our list of medications that cause gynecomastia. Do not stop a prescribed medicine on your own. Bring the list to your appointment and let the prescribing doctor decide whether a change makes sense.

The second group is local. The problem sits in the duct or the tissue right behind the nipple. An intraductal papilloma is a small benign growth inside one duct and is a common cause of clear or bloody discharge from a single opening. Duct ectasia, a widening and inflammation of the duct, tends to produce thicker, darker fluid. Infection produces pus with pain, heat, and redness. Male breast cancer is the diagnosis nobody wants to miss, and it most often shows up as discharge from one side, frequently bloody, sometimes with a lump.

What does the color of nipple discharge mean in men?

The color of nipple discharge in men gives a useful first clue but never settles the diagnosis. Milky fluid usually points to a hormonal cause such as high prolactin. Clear or watery fluid from one duct suggests a duct lesion. Bloody fluid needs prompt imaging. Yellow or green fluid with pain suggests infection.

What matters as much as color is pattern. Discharge from both nipples and from several ducts, especially when it only appears with squeezing, leans toward a hormonal or benign cause. Discharge from one nipple, from a single duct, that appears on its own and stains clothing leans toward a structural problem in that duct. The StatPearls authors describe the same distinction between physiologic and pathologic discharge.

Bloody discharge deserves special mention. In women it is most often caused by a benign papilloma. Men develop breast cancer far less often than women, but because male breast tissue is small and men rarely have papillomas, published case reports advise treating bloody discharge in a man as suspicious until tissue shows otherwise. That is not a reason to panic. It is a reason not to wait.

Can gynecomastia cause nipple discharge?

Gynecomastia by itself rarely causes nipple discharge. Enlarged male breast gland is usually dry. When a man has both gynecomastia and discharge, a shared hormonal cause is the usual explanation, most often high prolactin, a medication, an underactive thyroid, or anabolic steroid and SARM use, and that cause needs to be identified before any surgery.

In my practice, gynecomastia shows up as a firm, rubbery disc under the nipple, sometimes tender, sometimes puffy. It does not usually leak. So when a patient tells me he has both, I treat the discharge as a separate finding that needs its own explanation. Our guide to a lump under the nipple in men walks through how we tell gland from other causes of a mass.

Men using anabolic steroids, prohormones, or SARMs are a group where both problems can appear together, because some compounds raise prolactin or estrogen activity. If that applies to you, say so at the consultation. It changes the bloodwork we order and the timing of surgery. Our article on gynecomastia from steroids explains why the hormones need to be stable first.

Discharge is also one of the features that separates a simple gynecomastia lump from something that needs a biopsy. Our page on gynecomastia lump vs cancer lists the others: a hard or fixed mass, a lump off to one side of the nipple, skin dimpling, and a nipple that has recently pulled inward.

When should a man worry about nipple discharge?

A man should arrange a prompt medical exam for any nipple discharge, and should be seen within days if the discharge is bloody, comes from one nipple on its own, occurs with a lump, or comes with nipple retraction, skin dimpling, a rash on the nipple, or a swollen lymph node in the armpit.

Fever, spreading redness, and severe pain with thick discharge suggest an infection or abscess, and those need to be seen the same day or the next. Headaches or changes in peripheral vision alongside milky discharge can point to a pituitary tumor pressing on the optic nerves, which also warrants a quick evaluation.

Men with a family history of breast cancer, a known BRCA mutation, prior chest radiation, or Klinefelter syndrome carry a higher baseline risk of male breast cancer, and should have a lower threshold for imaging.

How is nipple discharge in men diagnosed?

Nipple discharge in men is diagnosed with a history and physical exam, blood tests for prolactin, thyroid, kidney, liver, and sex hormones, and breast imaging with ultrasound and usually a diagnostic mammogram. If imaging shows a lesion, a needle biopsy follows. Milky discharge with high prolactin leads to a pituitary MRI.

The visit starts with questions. How long it has been happening, one side or both, spontaneous or only with squeezing, the color, every medication and supplement, any steroid or SARM use, and family history. Then the exam: both sides of the chest, the nipple and areola, and the armpits. If there is fluid, I note which duct it comes from.

Blood work sorts out the hormonal causes. In men, imaging of the chest is usually ultrasound first, with mammography added in most cases because the two tests see different things. The same approach is laid out in our page on how gynecomastia is diagnosed, since the two workups overlap heavily. Fluid can be sent for cytology, although a normal result does not rule out a problem on its own, so imaging still matters.

How is nipple discharge in men treated?

Treatment of nipple discharge in men depends entirely on the cause. Hormonal causes are treated medically, for example with dopamine agonist medication for a prolactinoma or thyroid replacement for hypothyroidism. Infections are treated with antibiotics and drainage. Duct lesions are removed surgically. Cancer is treated by a breast oncology team.

When a medication is responsible, the prescribing physician may be able to switch to an alternative, and the discharge often settles once prolactin comes down. When a single duct is the source, the surgical answer is to remove that duct, which also provides tissue for diagnosis. When cancer is found, care moves to a breast surgical oncology team, and I help coordinate that referral.

Once the discharge has been explained and treated, some men are left with established gynecomastia that has not gone away on its own. That is when surgery to remove the gland is appropriate, and not before. You can read what that operation involves on our gynecomastia surgery in Los Angeles page.

What to do next

If you have noticed fluid from your nipple, stop squeezing it, write down what you have seen, and gather a list of your medications and supplements. Then book an exam with a physician who will do the bloodwork and imaging rather than simply reassure you. MedlinePlus gives a patient-level overview of the same warning signs if you want to read further before your appointment.

Dr. Babak Moeinolmolki, MD, FACS, is double board-certified through the American Board of Cosmetic Surgery (ABCS) and the American Board of General Surgery, and evaluates male chest concerns, including nipple discharge and gynecomastia, in Los Angeles. Any surgeon’s certification can be verified independently through the certifying board’s public directory.

Contact the practice to arrange a consultation.

* Illustrative images on this page are models, not actual patients. Real patient results are shown in our Before & After gallery.