Galactorrhea happens when milk or a milk-like discharge leaks from your nipples. It’s different from regular milk secretion that happens during and after pregnancy. While it can affect all sexes, it tends to occur more often in women between the ages of 20 and 35.

While unexpectedly seeing what looks like milk coming out your nipples can be alarming, it’s often nothing to worry about. But in rare cases, it may be a sign of an underlying condition that needs treatment.

The main symptom of galactorrhea is a white substance coming out of your nipple.

This discharge can:

  • leak either occasionally or almost constantly
  • come out of one or both nipples
  • range in amount from light to heavy

You may have other symptoms as well, depending on the underlying cause.

Several things can cause galactorrhea in all sexes. Keep in mind that some people have what doctors call idiopathic galactorrhea. This is galactorrhea without any clear cause. Your breast tissue may simply be more sensitive to certain hormones.

Prolactinoma

Galactorrhea is often caused by a prolactinoma. This is a tumor that forms in your pituitary gland. It can press on your pituitary gland, stimulating it to produce more prolactin. Prolactin is the hormone that’s largely responsible for lactation.

In females, a prolactinoma can also cause:

  • infrequent or absent periods
  • low libido
  • fertility problems
  • excessive hair growth

Males may also notice:

  • low libido
  • erectile dysfunction

If it grows large enough to put pressure on the nerves in your brain near your pituitary gland, you may also notice frequent headaches or vision changes.

Other tumors

Other tumors can also press on your pituitary gland’s stalk, where it connects to the hypothalamus, an area at the base of your brain. This can stop the production of dopamine. In addition to regulating your emotions, dopamine also helps to keep your prolactin levels in check by decreasing them as necessary.

If you aren’t producing enough dopamine, your pituitary gland may produce too much prolactin, resulting in nipple discharge.

Other causes in both sexes

Many other conditions can cause you to have too much prolactin. These include:

  • hypothyroidism, which happens when the thyroid gland doesn’t work to full capacity
  • taking certain high blood pressure medications, such as methyldopa (Aldomet)
  • long-term kidney conditions
  • liver disorders, such as cirrhosis
  • some types of lung cancer
  • taking opioid medications, such as oxycodone (Percocet) and fentanyl (Actiq)
  • taking certain antidepressants, such as paroxetine (Paxil) or selective serotonin reuptake inhibitors (SSRIs), such as citalopram (Celexa)
  • using cocaine or marijuana
  • taking certain herbal supplements, including fennel or anise seed
  • taking prokinetics for gastrointestinal conditions
  • using phenothiazines to get rid of parasites

In females

Taking birth control pills impacts different hormone levels, which can cause galactorrhea in some females.

In males

Male hypogonadism refers to having low testosterone. This is one of the more common causes of galactorrhea in males. It can also cause gynecomastia, which enlarges the breasts.

In newborns

Galactorrhea is also often seen in newborns. This can be a result of the mother’s heightened estrogen during pregnancy. If it enters the placenta, it can get into a baby’s blood before birth. This can bring about both enlarged breasts and nipple discharge.

Galactorrhea is usually a sign of an underlying health issue, so it’s important to work with a doctor to pinpoint the cause.

They’ll likely use a combination of the following exams and tests to make a diagnosis:

  • A full physical. Your doctor will likely see how your nipple responds to being squeezed, and whether that causes more discharge to come out. They may also examine your breasts for any signs of a tumor.
  • Blood tests. Testing your prolactin and thyroid-stimulating hormone levels can help to further narrow down the potential cause.
  • Lab tests of the nipple discharge. If you’ve been pregnant in the past, they may take a sample of your nipple discharge and examine it for bits of fat. This is a tell-tale sign of galactorrhea, helping to differentiate it from lactation.
  • Imaging test. An MRI or CT scan can help to check for prolactinomas or other tumors near your pituitary gland or check your breast tissue for anything unusual. A mammogram or ultrasound can help to identify any unusual lumps or breast tissue.
  • Pregnancy tests. If there’s any chance you may be pregnant, your doctor might want to use a pregnancy test to rule out lactation.

Treating galactorrhea depends on the cause. But if you have a small prolactinoma that it’s causing any other symptoms, the condition might resolve on its own.

Some other potential treatments for galactorrhea include:

  • Avoiding medications that may be causing the discharge. If you suspect a medication you take might be causing galactorrhea, work with your doctor to see if there’s another you can take instead. Just make sure you don’t stop taking anything abruptly, as this can lead to other unintended side effects.
  • Taking medication to decrease or stop prolactin by increasing your levels of dopamine. Common examples include bromocriptine (Cycloset) or cabergoline (Dostinex). These medications can help to shrink prolactinomas and other tumors. They can also help to regulate your prolactin levels.
  • Surgery to remove a prolactinoma or other tumor. If medication doesn’t seem to work or the tumor is too large, you may need surgery to remove it.

Once they determine the cause, most people with galactorrhea make a full recovery. Pituitary gland tumors are often harmless, and medication can often help to manage any symptoms they cause. In the meantime, try to avoid doing anything that creates more nipple discharge, such as stimulating your nipples during sex or wearing tight clothing.