Cushing's syndrome happens when there is too much cortisol in the body. The disorder often starts with the pituitary gland. A tumor in the gland makes too much adrenocorticotropin hormone. That causes the adrenal glands to make too many corticosteroids.
Another main cause is taking glucocorticoids medicine, such as prednisone or dexamethasone, for a long time. These medicines are used to treat chronic diseases, such as severe allergies, asthma, severe arthritis, or immune system disorders. Other causes of Cushing's syndrome include:
- Certain kinds of cancer.
- Tumor on an adrenal gland.
- An inherited endocrine disorder.
- Certain chronic conditions, such as inflammatory bowel disease, lupus, or rheumatoid arthritis.