There are several possible causes of Cushing's syndrome. Cushing's syndrome can be caused by taking glucocorticoid hormones, such as prednisone. Some conditions for which glucocorticoids are taken for a long period of time include:
Systemic lupus erythematosus (lupus or SLE for short) and other inflammatory diseases
Immunosuppression after transplantation.
Other people develop Cushing's syndrome because of an overproduction of cortisol by the body. Some of the common causes of Cushing's syndrome in which the body produces too much cortisol include: