Cushing’s syndrome is a rare condition that develops when your body has too much cortisol, a hormone your body needs to respond to stress and keep many systems running properly. This hormone imbalance can lead to noticeable changes in appearance, energy levels, and overall health, making everyday activities more challenging.

How Common Is Cushing’s Syndrome?

Cushing’s syndrome is an uncommon condition. It affects somewhere between 40 and 70 people out of every 1 million each year, though some experts believe the actual number may be higher because the condition often goes undiagnosed for years^[1][2]. The disease can affect anyone, but it is most often found in adults between the ages of 25 and 50, with some sources noting it typically appears between ages 30 and 50^[2][3]. Women are affected much more often than men, making up about 70% of all cases^[2].

Children can also develop Cushing’s syndrome, though this is rare. When children do get it, their main symptoms are often obesity and being shorter than expected for their age^[1][5].

People who have type 2 diabetes along with high blood pressure and blood sugar levels that remain too high over time may have undiagnosed Cushing’s syndrome as the underlying cause^[3]. This overlap makes it important for doctors to consider Cushing’s syndrome when these conditions appear together.

What Causes Cushing’s Syndrome?

Cushing’s syndrome happens when your body is exposed to too much cortisol over a long period. The causes can be divided into two main groups: those coming from outside your body and those developing inside it.

The most common cause overall is taking high doses of steroid medicines (also called glucocorticoids) for an extended time^[1][5]. Doctors prescribe these medications to treat conditions like asthma, rheumatoid arthritis, lupus, and other autoimmune diseases. More than 10 million Americans take these medicines each year, though not all of them develop Cushing’s syndrome^[3]. When steroid medicines cause the condition, it’s called exogenous Cushing’s syndrome, meaning the excess cortisol comes from outside the body^[9].

When the condition develops because your own body makes too much cortisol, it’s called endogenous Cushing’s syndrome^[3]. Several internal problems can cause this. The most common is a small, non-cancerous growth called a tumor in the pituitary gland, which sits near your brain^[1][5]. This tumor releases too much of a hormone called ACTH (adrenocorticotropic hormone), which then signals your adrenal glands to produce excessive cortisol. When a pituitary tumor causes the problem, doctors specifically call it Cushing’s disease, which accounts for about 70% of all endogenous cases in adults^[2][4].

Tumors can also develop in other parts of the body. Sometimes a tumor grows in one of the two adrenal glands themselves, which sit on top of your kidneys and normally produce cortisol^[5][9]. Less commonly, a tumor elsewhere in the body, such as in the lungs or pancreas, can produce ACTH, triggering excess cortisol production. This is called ectopic Cushing’s syndrome^[4][9].

In some people, cortisol levels vary greatly over time, sometimes over months or even years. This pattern is called cyclical Cushing’s syndrome and can make diagnosis particularly difficult because symptoms come and go depending on cortisol levels^[9].

Who Is at Higher Risk?

Several factors increase the likelihood of developing Cushing’s syndrome. People who take cortisol-like medications such as prednisone or hydrocortisone for conditions like asthma and rheumatoid arthritis are especially vulnerable to developing the condition^[2][5]. The longer you take these medicines and the higher the dose, the greater your risk.

Women face a higher risk than men, accounting for roughly three times as many cases^[2][4]. The reasons for this difference are not well understood. Adults in their mid-twenties to early fifties are the age group most commonly affected, though the condition can develop at any age^[2].

People who have type 2 diabetes combined with high blood pressure and persistently elevated blood sugar may have underlying Cushing’s syndrome causing or worsening these problems^[3]. Anyone with a tumor in the pituitary gland, adrenal glands, or certain other organs also faces increased risk of developing the syndrome.

Common Signs and Symptoms

The symptoms of Cushing’s syndrome typically develop gradually, which is why the condition often goes undiagnosed for several years. On average, people experience symptoms for three to five years before getting a proper diagnosis^[25]. The wide range of symptoms can affect many parts of your body and significantly impact daily life.

One of the most noticeable signs is unexpected weight gain, especially around your midsection, upper back, chest, and neck^[1][2]. Your arms and legs may actually look thin compared to the rest of your body because muscle breaks down while fat accumulates in the center. Many people develop what’s called a “moon face,” meaning the face becomes rounder and fuller. A fatty lump may also form between the shoulders, sometimes referred to as a “buffalo hump”^[1].

Skin changes are common and can be quite distinctive. You may notice pink or purple stretch marks appearing on your stomach, hips, thighs, breasts, and underarms^[1][5]. Your skin becomes thin and fragile, bruising easily even from minor bumps. Wounds and cuts heal slowly, and acne may develop or worsen.

Fatigue and muscle weakness are frequent complaints. You may feel tired all the time, and your muscles, particularly in your upper arms and legs, become weak, making it harder to climb stairs, get up from a chair, or carry objects^[1][2]. Physical activities that were once easy may become exhausting.

Emotional and mental changes can be just as troubling as physical symptoms. Many people experience mood swings, feeling irritable, anxious, or depressed^[1][5]. You might have difficulty concentrating or remembering things, a feeling some describe as “mind fog”^[17]. These cognitive symptoms can affect your performance at work or in daily tasks.

Women may notice irregular menstrual periods or their periods may stop completely. Excessive hair growth on the face and body, a condition called hirsutism, is another possible symptom in women^[1][5]. Men may experience erectile dysfunction and a reduced sex drive. Both men and women often report a loss of libido^[5].

Other symptoms can include high blood pressure, elevated blood sugar levels, frequent infections, and sleep problems such as insomnia or waking during the night and being unable to fall back asleep^[2][22]. Some people feel hot and sweaty more often than usual.

How to Prevent Cushing’s Syndrome

Because Cushing’s syndrome caused by tumors develops inside the body without known environmental triggers, there is no way to prevent these cases^[9]. The condition is not hereditary, meaning it doesn’t run in families.

However, when Cushing’s syndrome results from taking steroid medications, careful management of these medicines can help reduce risk. If you need to take glucocorticoid medicines for conditions like asthma, arthritis, or autoimmune diseases, work closely with your doctor to use the lowest effective dose for the shortest time possible. Never adjust your steroid medication doses on your own, as this can be dangerous. Your healthcare provider can monitor you for early signs of cortisol excess and make adjustments to your treatment plan as needed.

Regular check-ups with your doctor are important if you’re on long-term steroid therapy. During these visits, your healthcare provider can watch for symptoms of developing Cushing’s syndrome and take steps to prevent complications.

Understanding What Happens in Your Body

To understand Cushing’s syndrome, it helps to know how cortisol normally works in your body. Cortisol is a steroid hormone produced by your adrenal glands, which are small organs sitting on top of each kidney^[2][3]. Often called the “stress hormone,” cortisol plays many vital roles in keeping you healthy.

When you face stress, your body releases extra cortisol to help you cope. This hormone increases your heart rate and blood pressure, manages your blood sugar, helps you breathe, and temporarily shuts down systems you don’t immediately need during stressful situations, like digestion and reproduction^[2]. Cortisol also helps regulate your immune system, reduces inflammation, assists with memory formation, balances salt in your body, and helps convert the food you eat into energy^[2][3].

Cortisol levels naturally rise and fall throughout the day. In healthy people, cortisol is typically highest in the morning when you wake up and lowest in the evening^[10]. This normal rhythm helps regulate your sleep-wake cycle.

Three parts of your body work together to control cortisol levels: the hypothalamus (a part of your brain above the pituitary gland), the pituitary gland (in your brain), and the adrenal glands^[2]. In Cushing’s syndrome, this control system breaks down. When you have too much cortisol circulating in your body for a long time, the hormone that should help you in short bursts instead causes harm to many body systems.

Excess cortisol interferes with how your body processes fats, proteins, and carbohydrates, leading to weight gain in unusual patterns and muscle breakdown^[22]. It affects your bones, making them weak and more likely to break. High cortisol disrupts your metabolism, contributing to high blood sugar and potentially leading to type 2 diabetes. It weakens your immune system, making you more prone to infections. The hormone also affects your brain chemistry, contributing to mood changes, depression, anxiety, and problems with memory and concentration.

The physical changes you can see on the outside—the rounded face, central weight gain, thin skin, and stretch marks—are visible signs of these deeper disruptions happening throughout your body’s systems. Without treatment, these changes continue and worsen over time, affecting your quality of life and potentially leading to serious complications.