Cushing syndrome occurs when your body is exposed to high levels of the hormone cortisol for a long time. Cushing syndrome, sometimes called hypercortisolism, may be caused by the use of oral corticosteroid medication. The condition can also occur when your body makes too much cortisol on its own.
Too much cortisol can produce some of the hallmark signs of Cushing syndrome — a fatty hump between your shoulders, a rounded face, and pink or purple stretch marks on your skin. Cushing syndrome can also result in high blood pressure, bone loss and, on occasion, type 2 diabetes.
Treatments for Cushing syndrome can return your body's cortisol production to normal and noticeably improve your symptoms. The earlier treatment begins, the better your chances for recovery.
The signs and symptoms of Cushing syndrome can vary depending on the levels of excess cortisol.
Common signs and symptoms involve progressive obesity and skin changes, such as:
- Weight gain and fatty tissue deposits, particularly around the midsection and upper back, in the face (moon face), and between the shoulders (buffalo hump)
- Pink or purple stretch marks (striae) on the skin of the abdomen, thighs, breasts and arms
- Thinning, fragile skin that bruises easily
- Slow healing of cuts, insect bites and infections
Women with Cushing syndrome may experience:
- Thicker or more visible body and facial hair (hirsutism)
- Irregular or absent menstrual periods
Men with Cushing syndrome may experience:
- Decreased libido
- Decreased fertility
- Erectile dysfunction
Other signs and symptoms include:
- Severe fatigue
- Muscle weakness
- Depression, anxiety and irritability
- Loss of emotional control
- Cognitive difficulties
- New or worsened high blood pressure
- Bone loss, leading to fractures over time
- In children, impaired growth
When to see a doctor
Contact your doctor if you have symptoms that suggest Cushing syndrome, especially if you're taking corticosteroid medication to treat a condition, such as asthma, arthritis or inflammatory bowel disease.
Excess levels of the hormone cortisol are responsible for Cushing syndrome. Cortisol, which is produced in the adrenal glands, plays a variety of roles in your body. For example, cortisol helps regulate your blood pressure and keeps your cardiovascular system functioning normally.
Cortisol also helps your body respond to stress and regulates the way you convert (metabolize) proteins, carbohydrates and fats in your diet into usable energy. However, when the level of cortisol is too high in your body, you may develop Cushing syndrome.
The role of corticosteroid medications
Cushing syndrome can develop from a cause outside of your body (exogenous Cushing syndrome). One example is taking oral corticosteroid medications in high doses over an extended period of time. These medications, such as prednisone, have the same effect in the body as does cortisol produced by your body.
Oral corticosteroids may be necessary to treat inflammatory diseases, such as rheumatoid arthritis, lupus and asthma, or to prevent your body from rejecting a transplanted organ. Because the doses required to treat these conditions are often higher than the amount of cortisol your body normally needs each day, side effects from excess cortisol can occur.
It's also possible to develop Cushing syndrome from injectable corticosteroids — for example, repeated injections for joint pain, bursitis and back pain. Inhaled steroid medicines (taken for asthma) and steroid skin creams (used for skin disorders such as eczema) are generally less likely to cause Cushing syndrome than oral corticosteroids. But, in some individuals, these medications may cause Cushing syndrome, especially if taken in high doses.
Your body's own overproduction
The condition may also be due to your body's own overproduction of cortisol (endogenous Cushing syndrome). This may occur from excess production by one or both adrenal glands, or overproduction of the adrenocorticotropic hormone (ACTH), which normally regulates cortisol production, In these cases, Cushing syndrome may be related to:
- A pituitary gland tumor (pituitary adenoma). A noncancerous (benign) tumor of the pituitary gland, located at the base of the brain, secretes an excess amount of ACTH, which in turn stimulates the adrenal glands to make more cortisol. When this form of the syndrome develops, it's called Cushing disease. It occurs much more often in women and is the most common form of endogenous Cushing syndrome.
- An ectopic ACTH-secreting tumor. Rarely, when a tumor develops in an organ that normally does not produce ACTH, the tumor will begin to secrete this hormone in excess, resulting in Cushing syndrome. These tumors, which can be noncancerous (benign) or cancerous (malignant), are usually found in the lungs, pancreas, thyroid or thymus gland.
A primary adrenal gland disease. In some people, the cause of Cushing syndrome is excess cortisol secretion that doesn't depend on stimulation from ACTH and is associated with disorders of the adrenal glands. The most common of these disorders is a noncancerous tumor of the adrenal cortex, called an adrenal adenoma.
Cancerous tumors of the adrenal cortex (adrenocortical carcinomas) are rare, but they can cause Cushing syndrome as well. Occasionally, benign, nodular enlargement of both adrenal glands can result in Cushing syndrome.
- Familial Cushing syndrome. Rarely, people inherit a tendency to develop tumors on one or more of their endocrine glands, affecting cortisol levels and causing Cushing syndrome.
Without treatment, complications of Cushing syndrome may include:
- Bone loss (osteoporosis), which can result in unusual bone fractures, such as rib fractures and fractures of the bones in the feet
- High blood pressure (hypertension)
- Type 2 diabetes
- Frequent or unusual infections
- Loss of muscle mass and strength