What causes Cushing's syndrome?
The most common cause of Cushing's syndrome is taking corticosteroids orally (by mouth) every day for weeks to months. These medicines are usually prescribed to treat inflammatory disease, such as lupus and rheumatoid arthritis. Prednisone is the most common corticosteroid medicine that's taken this way. Other medicines include dexamethasone and methylprednisone.
Inhaled steroid medicines for asthma and steroid skin creams for eczema and other skin conditions don't usually cause Cushing's syndrome. Even oral medicines taken every day for short periods of time or every other day for longer periods don't often cause Cushing's syndrome.
The next most common cause of Cushing's syndrome is when the body makes too much cortisol. A tumor in the pituitary gland can be one cause of Cushing's syndrome. The pituitary gland is located at the bottom of the brain and controls the body's production of cortisol. These small tumors can cause the adrenal glands, which are near the kidneys, to make too much cortisol.
The tumors on the pituitary gland in Cushing's syndrome aren't usually malignant (cancercous). However, if these tumors get too big, they can cause problems with your eyesight.
Cushing's Disease: Clinical Manifestations and Diagnostic Evaluation by LF Kirk, Jr., M.D., RB Hash, M.D., HP Katner, M.D., and T Jones, M.D. (American Family Physician September 01, 2000, http://www.aafp.org/afp/20000901/1119.html)
Written by familydoctor.org editorial staff