The difference between Primary and Secondary Addison's

Canine Addison's Disease FAQ

Q. What's the difference between primary and secondary Addison's Disease?

A. Primary Addison's occurs as a result of the adrenals ceasing to function--this may be from immune-mediated destruction of the adrenals as well as the destruction of the adrenals from other diseases or cancer.

Secondary Addison's occurs because something else in the body causes the adrenals to stop functioning; for instance, a reduced secretion of ACTH by the pituitary gland or reduced secretion of corticotropin-releasing factor (CRF) by the hypothalamus. There is also secondary iatrogenic (iatrogenic: arising as a result of medical treatment). The adrenals may atrophy as a result of chronically receiving quantities of corticosteroids sufficient to suppress pituitary ACTH secretion.