Why does corticosteroids cause adrenal atrophy?

Corticosteroids can cause adrenal atrophy due to their effect on the hypothalamic-pituitary-adrenal (HPA) axis. When exogenous corticosteroids are introduced, they suppress the production of adrenocorticotropic hormone (ACTH) from the pituitary gland, which in turn reduces stimulation of the adrenal glands. Prolonged suppression leads to decreased adrenal gland size and function, resulting in atrophy. This is a consequence of the body's feedback mechanism to maintain hormonal balance.