What Causes Cushing’s Syndrome?

Medically Reviewed by Jabeen Begum, MD on April 19, 2024
7 min read

Cushing's syndrome is a hormonal disorder caused by high levels of the hormone cortisol in your body. It’s also known as hypercortisolism. Cortisol comes from your adrenal glands, which sit on top of your kidneys. It helps your body:

But when you have too much cortisol, it can throw off your body's other systems.

Most cases of Cushing's syndrome can be cured, though it may take some time for your symptoms to ease up.

The condition is more common in people assigned female at birth than those assigned male at birth. It's most often seen in people aged 25-40.

You can get Cushing's syndrome when there’s too much cortisol in your body for too long.

The most common cause is related to medications called glucocorticoids, also commonly known as corticosteroids or steroids (for example, prednisone).

These prescription steroids are used for conditions such as asthma, rheumatoid arthritis, lupus, or after an organ transplant. They’re powerful anti-inflammatory medications. Taking too much for too long can lead to Cushing's syndrome.

Although rare, you can also get Cushing’s syndrome from injectable steroids, such as repeated shots for joint pain, bursitis, and back pain.

Steroid skin creams, used for eczema and other skin problems, are less likely to cause Cushing’s syndrome, but it can happen.

A tumor in your pituitary gland (found at the base of the brain) or a tumor in the adrenal glands, can also prompt your body to make too much cortisol, which can lead to Cushing’s.

Adrenocorticotropic hormone (ACTH) is a hormone that regulates cortisol. In rare cases, an ACTH-secreting tumor causes Cushing’s syndrome. This kind of tumor can form in an organ that doesn’t naturally produce ACTH, but because of the tumor, it begins to make a lot of it. These tumors can be cancerous or noncancerous. They’re usually found in the lungs, pancreas, thyroid, or thymus gland.

It's not usually a condition that's passed along in families. But in some rare cases, people have it because a problem in their genes makes them more likely to get tumors on their glands.

Your case might be different than someone else's, but when the disease is full-blown, common symptoms are:

Your skin could become thin, heal slowly, and bruise easily. You might get purple or pink stretch marks all over your body, especially on your belly, thighs, arms, and chest.

Your bones may get weak. Everyday movements such as bending, lifting, or even getting out of a chair can cause backaches or breaks in your ribs or spine.

Children who have Cushing’s syndrome often have obesity and tend to grow slowly.

It might take several appointments to settle on your diagnosis.

When you go to your doctor, they'll do a physical exam and ask you questions, such as:

  • What symptoms have you noticed?
  • When did you first see them?
  • Does anything make them better? Or worse?
  • Are you feeling more emotional?
  • What medications are you taking?

If your doctor thinks you may have Cushing’s syndrome, they will probably recommend some of these tests:

24-hour urinary free cortisol test. This common test collects your urine for 24 hours to measure cortisol levels in it.

Dexamethasone suppression test. You’ll take a low-dose steroid pill at 11:00 p.m. and then take a blood test in the morning to see how much cortisol your body still makes.

Late-night salivary cortisol level. This test measures cortisol levels in your saliva. As the name suggests, these tests happen at night.

If you have Cushing's syndrome, your doctor may refer you to a specialist who will do other blood tests or imaging scans to find out what's causing it.

  • A blood test checks levels of the cortisol-regulating hormone ACTH. If levels are low, an adrenal tumor is the likely cause. If they’re normal or high, it’s probably a pituitary or ectopic tumor.
  • A corticotropin-releasing hormone (CRH) stimulation test is one way to tell the difference between a pituitary and ectopic tumor.
  • A high-dose dexamethasone suppression test is another way to tell the difference between a pituitary and ectopic tumor.
  • Imaging tests are sometimes done to look for tumors.
  • A test called petrosal sinus sampling takes blood samples from veins close to the pituitary and far from it. You’ll also get a shot of CRH, the hormone that causes the pituitary to release ACTH. Levels of ACTH in the blood samples help tell whether it’s a pituitary or an ectopic tumor.

Cushing’s disease vs. Cushing’s syndrome

Cushing's disease is a type of Cushing's syndrome. It happens when there's a tumor in the pituitary gland, which makes your body produce too much cortisol. It's the most common kind of Cushing' syndrome that comes from inside the body, making up around 70% of cases.

You can ask your doctor the following questions:

  • Will my symptoms change? If so, how?
  • What are my treatment options? Which do you recommend?
  • How will we know if they're working?
  • Do these treatments have side effects? What can I do about them?
  • When will I start to feel better?
  • Does this condition put me at risk for any others?

The first thing your doctor will figure out is why you have too much cortisol. That will lead to how to treat your condition.

  • If you have too much cortisol because you're taking steroid medicines, your doctor will check to see if you can slowly lower your dose while still managing your asthma, arthritis, or other conditions.
  • You may need surgery to remove a tumor.
  • You may have radiation alongside surgery if your doctor can't completely remove the tumor. They'll use it instead of surgery in some cases.
  • Medications to control cortisol production may be an option when surgery and radiation don’t work. These medications can have serious side effects. A doctor may also prescribe medications before surgery to people who are very sick with Cushing’s syndrome.
  • In some cases, the tumor or its treatment will affect other hormones produced by the pituitary or adrenal gland, and you may need hormone replacement medication.

Lifestyle changes

Some lifestyle changes may help you manage your Cushing’s syndrome and stay healthier:

  • Soothe aches and pains with hot baths, massages, and gentle exercises such as water aerobics and tai chi.
  • Let your family and friends know what you're going through. Ask for their support, and let them know how they can help.
  • Take time for the people and activities you enjoy. It's OK to say no and set limits to keep your energy up. If you're feeling overwhelmed, talk to a counselor or therapist. Your doctor may be able to give you a referral.

Eating well is an important part of living with Cushing's. A healthy diet can ease some symptoms and prevent others. Protect your bones by eating foods with calcium and vitamin D. Limit how much sodium and fatty foods you eat. A nutritionist can help you ensure you're getting plenty of the right nutrients.

Foods with calcium

  • Dairy products
  • Fortified plant-based milk
  • Calcium-fortified orange juice
  • Winter squash
  • Edamame
  • Tofu made with calcium sulfate
  • Canned sardines
  • Salmon with bones
  • Almonds
  • Leafy greens

Foods with vitamin D

  • Cod liver oil
  • Salmon
  • Swordfish
  • Tuna
  • Vitamin D-fortified orange juice
  • Vitamin D-fortified dairy and plant milk
  • Sardines
  • Beef liver
  • Egg yolk
  • Fortified cereals

Cushing’s syndrome can cause serious health problems and even death if not treated. Problems may include:

Your symptoms and how long they'll last depend on:

  • The amount of extra cortisol you have
  • The cause of your high cortisol
  • How long you've had the condition
  • Your overall health

Most of the time, Cushing’s syndrome can be treated and cured.

If your Cushing's syndrome isn't curable, you'll want to look for ways to manage your weight gain, muscle weakness, and tiredness. Discuss the same with your doctor, and tell them how you feel. If you get depressed, it's important to get treated for that.

Look for ways to connect online and in person with people who have experience with Cushing's syndrome. You can learn more about living with the condition and meet other people who have it, in forums on the Cushing’s Support & Research Foundation website.

Cushing's syndrome is a hormonal disorder caused by too much cortisol in the body. This hormone helps regulate various bodily functions, but too much can disrupt other systems. Taking certain medications, such as steroids, for conditions such as asthma or lupus commonly causes Cushing's syndrome. Treatment for the condition depends on the underlying cause and may include surgery, medication, or lifestyle changes. With proper management, most cases can be cured.