Hyperadrenocorticism (Cushing's disease) is a common endocrine disorder in older dogs caused by excess cortisol production, leading to significant physical changes and a reduced quality of life that is substantially improved by treatment.
Cushing's disease causes a slow but progressive deterioration in physical comfort and quality of life. Dogs develop a pendulous abdomen, lose muscle mass, struggle to exercise, and may develop skin so fragile it tears easily. The increased cortisol impairs immune function, making infections more likely and harder to resolve. Many owners attribute these signs to normal aging and do not seek diagnosis, meaning many dogs live for years with uncontrolled disease. Effective management with trilostane dramatically reverses most signs and restores quality of life. Regular monitoring of adrenal function is essential since over-suppression of cortisol with medication can cause an Addisonian crisis, which is life-threatening.