Cushing's Syndrome in Dogs

Cushing’s syndrome, also called hyperadrenocorticism, occurs when your dog’s adrenal glands produce too much cortisol, an essential hormone released in response to stress. While cortisol is needed for normal bodily functions, too much cortisol can cause serious health consequences.

The majority of of all Cushing’s syndrome cases (80% to 85%) are caused by a small, benign tumor located in the pituitary gland, found at the base of the brain. This noncancerous tumor produces a hormone that stimulates the adrenal glands to enlarge and produce too much cortisol.

In the remaining 15% to 20% of dogs with Cushing’s, the cause is a malignant tumor affecting one of the adrenal glands, causing the gland to produce too much cortisol.

In some cases, Cushing’s syndrome can be caused by the long-term use of steroid medications (e.g. prednisone) to treat many conditions such as allergies, inflammation, and autoimmune disease.

Cushing’s disorder can be hard to spot. The symptoms are variable and can be mistaken for other common problems. Often, the symptoms are erroneously thought of as old age.

If your dog has Cushing’s syndrome, you may notice any of the following symptoms:

  • Increased thirst
  • Increased urination
  • Increased appetite
  • A pot-bellied appearance
  • Loss of hair along the back, near the tail
  • Darkening of the skin
  • Recurrent skin and urinary tract infections
  • Increased panting

Determining if your best friend has Cushing’s can be tricky as there isn’t one test that can absolutely diagnose it. Your veterinarian will take a complete history of your dog and perform a thorough physical exam.

Some of the diagnostic tests they may recommend are:

  • Chemistry tests to evaluate kidney, liver, and pancreatic function, as well as sugar levels
  • A complete blood count to rule out blood-related conditions
  • Electrolyte tests to ensure your pet isn’t dehydrated or suffering from an electrolyte imbalance
  • Urine tests to screen for urinary tract infection and other disease, and to evaluate the ability of the kidneys to concentrate urine
  • Urine tests to measure the amount of cortisol in the urine
  • A thyroid test to determine if the thyroid gland is producing too little thyroid hormone
  • Cortisol tests to evaluate your dog’s blood cortisol levels
  • Blood pressure measurement

Additionally, though less commonly, your veterinarian may recommend the following tests:

  • An ECG to screen for an abnormal heart rhythm, which may indicate underlying heart disease
  • Antibody tests to identify if your pet has been exposed to tick-related or other infectious disease

Once your pooch has been diagnosed with Cushing’s syndrome, your veterinarian will most likely prescribe a medication that will help regulate the levels of cortisol in his blood. In some cases, depending on the underlying cause, surgery may be suggested. It will be important to watch your dog closely once treatment begins. Be aware, too, that your veterinarian will most likely want to screen your dog routinely to monitor his response to treatment and tolerance of the medication.

There is no way to prevent Cushing’s syndrome, but you can help your veterinarian diagnose it earlier, which can potentially lead to more effective treatment options! As your pet ages, make sure he is seen routinely by your veterinarian, and watch for any symptoms of Cushing’s syndrome. Work with your veterinarian to establish a regular blood-screening schedule for your dog, which can help identify the onset of conditions or disease before your canine friend becomes symptomatic. Most important: if you have questions about Cushing’s syndrome or your dog’s health, contact your veterinarian.

If you have any questions or concerns, you should always visit or call your veterinarian – they are your best resource to ensure the health and well-being of your pets.