Cushing’s disease, also known as hyperadrenocorticism, occurs when the adrenal gland produces too much cortisol. Cushing’s disease is most often seen in dogs, although it can rarely affect cats.

In most cases, Cushing’s disease is caused by a benign tumor in the pituitary gland. The pituitary gland is responsible for signaling the adrenal glands to produce cortisol. In the event of a pituitary tumor, too much of that signal is sent to the adrenal glands, resulting in the overproduction of cortisol. A less common cause of Cushing’s disease is the overproduction of cortisol by a malignant tumor within one of the adrenal glands. It is also possible to cause Cushing’s disease with long-term, high dosing of steroid immunosuppressants, such as prednisone.



Cushing’s disease can sometimes be difficult to differentiate from other hormonal diseases, such as hypothyroidism. Your veterinarian will likely recommend baseline blood and urine tests, which include a thyroid hormone level. Additional diagnostics may include:


Treatment of pituitary-dependent Cushing’s disease is based on medically managing the body’s ability to produce cortisol. Cushing’s disease is generally well controlled through medication. However, regular follow-up with your veterinarian is necessary to ensure that the disease is being adequately managed, as overtreatment can destroy the adrenal gland and the subsequent onset of Addison’s disease. Undertreatment will fail to resolve the clinical symptoms.

Treatment of Cushing’s disease secondary to an adrenal tumor is best treated by surgical removal of the affected adrenal gland.