Merck Manuals: Answering Common Questions About Cushing Syndrome

RAHWAY, N.J., April 7, 2025 /PRNewswire/ -- High cortisol – and its deleterious effects on the body – may be a more commonly recognized phrase in today's healthcare lexicon. Still, doctors say there is a need for more awareness of a rare and potentially life-threatening condition involving cortisol, known as Cushing syndrome. 

In a new editorial from MerckManuals.com, Ashley B. Grossman, MD, University of Oxford; Fellow, Green-Templeton College, addresses common patient questions around Cushing syndrome.

1. What causes Cushing syndrome?

Adrenal glands release hormones that help control blood pressure, heart rate, balance of water and salt, response to stress, and more, says Grossman. Cushing syndrome occurs when these glands release too much of the hormone cortisol, or you are taking a hormone like cortisol.

This typically has one of two causes:

• a tumor in the adrenal glands or cancer in another part of the body
• taking a corticosteroid medicine for a long time

2. What are the symptoms of Cushing syndrome?

Cortisol is an essential hormone in the body. Having too much can cause many changes, including increases in blood sugar and cholesterol. Corticosteroids also alter the amount and distribution of body fat, says Grossman.

Other symptoms of Cushing syndrome include:

• Large round face (called a "moon face")
• Large amounts of belly fat and fat at the top of your back (often called a "buffalo hump")
• Thin skin that bruises easily and heals slowly
• Purple streaks that look like stretch marks on your chest and belly
• Getting tired easily
• Sometimes, extra face and body hair
• In females, sometimes sudden hair loss from their head

Cushing syndrome can be life-threatening, says Grossman. Very high cortisol will lower your potassium level, which can cause heart problems.

3. What can I expect at a doctor's appointment for Cushing syndrome?

For patients not taking high levels of steroids, Cushing syndrome is rare, and many symptoms can have other causes. At the same time, the physical changes can be a good indicator of Cushing syndrome, says Grossman. 

If you're experiencing these symptoms, it's a good idea to see your primary care doctor right away. Bring some photos of yourself from a few years ago so doctors can see how your body may have changed. Doctors will also ask about anything that could increase steroid levels, such as using creams with steroids or inhaled steroids, as well as recreational drug use.

Once a patient is diagnosed with Cushing syndrome, it's important to see a specialist for further guidance and treatment, says Grossman. Treatment will depend on whether the problem is in the adrenal glands, the pituitary gland, or elsewhere.

4. Is it safe to take steroids?

Steroids can be a game-changing treatment for many patients, but they do have a risk of side effects, says Grossman. They need to be taken as prescribed. Doctors never stop the use of corticosteroids abruptly if people have been taking them for more than two or three weeks. Instead, doctors gradually reduce (or taper) the dose over weeks and sometimes months.

To read more of Grossman's insights on Cushing syndrome, visit this editorial on MerckManuals.com.

About The Merck Manuals and MSD Manuals

First published in 1899 as a small reference book for physicians and pharmacists, The Merck Manual grew in size and scope to become one of the world's most widely used comprehensive medical resources for professionals and consumers. As The Manual evolved, it continually expanded the reach and depth of its offerings to reflect the mission of providing the best medical information to a wide cross-section of users, including medical professionals and students, veterinarians and veterinary students, and consumers. In 2015, The Manuals kicked off Global Medical Knowledge 2020, a global initiative with the goal to make the best current medical information accessible by up to three billion professionals and patients around the world by 2020. The Manuals achieved that goal, and today its medical information is available in nearly 250 countries and in 14 languages. It's continuing its ambitious mission through outreach, education and creating new reliable medical resources. For access to thousands of medical topics with images, videos and a constantly expanding set of resources, visit MerckManuals.com or MSDManuals.com and connect with us on social media: For Consumers in the U.S. and its territories: X (formerly Twitter) and Facebook. For Professionals in the U.S. and its territories: X (formerly Twitter) and Facebook

About Merck

At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than 130 years, we have brought hope to humanity through the development of important medicines and vaccines. We aspire to be the premier research-intensive biopharmaceutical company in the world – and today, we are at the forefront of research to deliver innovative health solutions that advance the prevention and treatment of diseases in people and animals. We foster a diverse and inclusive global workforce and operate responsibly every day to enable a safe, sustainable and healthy future for all people and communities. For more information, visit www.merck.com and connect with us on X (formerly Twitter), Facebook, Instagram, YouTube and LinkedIn.

SOURCE The Merck Manuals