What Causes Cushing Syndrome?

Cushing syndrome can be caused by endogenous (internal) and/or exogenous (external) factors.


  • Tumor of the adrenal gland
  • Too much adrenocorticotropic hormone (ACTH), a hormone made by the pituitary gland, that stimulates the adrenal glands to make cortisol
  • Other tumors that make too much ACTH
  • High levels of other hormones that increase ACTH production


  • Long-term use of moderate to high doses of medications called glucocorticoids. Glucocorticoids include hydrocortisone, prednisone, prednisolone, dexamethasone and other similar medications. These medications are used to reduce inflammation in conditions such as asthma, arthritis, inflammatory bowel disorders and connective tissue disorders. While taking these medications by mouth is the most common cause of Cushing syndrome, this condition also occurs with prolonged and heavy exposure to glucocorticoids applied on the skin or inhaled. Thus, it is very important to follow the directions of a health care professional to avoid overuse of such medications.

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Rev. 11/2019. MassGeneral Hospital for Children and Massachusetts General Hospital do not endorse any of the brands listed on this webpage. This webpage is intended to provide health information so that you can be better informed. It is not a substitute for medical advice and should not be used to treatment of any medical conditions.