Explaining Cushing’s Disease in Dogs: What Is It?

Sometimes called hyperadrenocorticism or Cushing’s syndrome, Cushing's disease is a common hormonal disorder found in both humans and animals.³ Hyperadrenocorticism roughly means “overactive adrenal gland.” The adrenal glands are near the kidneys and they act as the body’s manager of major hormones like cortisol. Dogs with Cushing's disease create too much cortisol. Too much of this hormone can make your dog very sick, causing kidney damage and diabetes.

Are you still scratching your head? Let’s discuss this disease and why it’s so important to catch the signs early.

Causes of Cushing’s Disease in Dogs

Some breeds of dogs (like miniature poodles and beagles) inherit Cushing's disease, but there are three causes of Cushing’s disease:³^,⁴

• A benign tumor on the pituitary gland at the base of the brain
• A tumor of the adrenal gland
• Long-term use of steroids (typically used as treatment for another medical issue)

Adult or senior dogs make up the majority of pets that get Cushing’s disease through tumors. As you can imagine, tumors affect the way the glands perform in the body. If the tumors are malignant, cancer can spread to other organs.

Symptoms of Cushing’s disease in dogs

Regardless of the cause, the symptoms of Cushing’s disease look identical. Here are most of the common symptoms of Cushing’s disease in dogs:³^,⁴

• Excessive thirst
• Frequent urination
• Increased appetite
• Avoiding the heat
• Lethargy
• A potbelly
• Panting
• Obesity
• Weakness
• Hair loss
• Thin skin
• Easily bruised

The most common signs are hair loss, frequent urination, and appetite changes. Speak to your veterinarian immediately if you notice any of these symptoms so they can begin testing for the disease.

Diagnosing Cushing’s Disease in Dogs

Your vet may need to conduct several tests to determine if your pup has Cushing’s disease, as this disorder is notoriously difficult to diagnose. Some tests, like a blood test or urinalysis, may need to be repeated every 3 to 6 months if the tests are inconclusive or if symptoms disappear.³ Repeat tests will make sure that something wasn’t missed from the first samples.

Two other common tests your vet may perform are an adrenocorticotropic hormone (ACTH) stimulation test and a low-dose dexamethasone suppression (LDDS) test.⁴ Both tests are designed to measure the level of excess cortisol in the body, along with how your dog’s body responds to hormones.

If all the test results lead to your dog potentially having Cushing’s disease, then your vet’s goal is to figure out what’s causing the disease. There are several diagnostic imaging tests that your care team may use to get a good look at your dog’s glands like X-rays, ultrasounds, CT scans, or an MRI.³^,⁴ All of these tests together will guide the next steps toward getting your dog healthy.

Treating Cushing’s Disease in Dogs

Vets can choose to treat Cushing’s disease with medication rather than surgery because removal of the tumors may be extremely risky.⁵ If the tumor is benign (meaning not spreading or cancerous), then monitoring the disease while you make lifestyle changes may be the best option for your dog.

Currently, Vetoryl (trilostane) is the only FDA-approved drug used to treat both pituitary-dependent and adrenal-dependent Cushing’s disease.⁵ The other approved medication is Anipryl (selegiline) but it is only recommended for “uncomplicated, pituitary-dependent” cases of Cushing’s disease.³^,⁵

Another option that vets use is human chemotherapy drugs, such as Lysodren (mitotane), which destroys the top layer of the glands.⁵ This route requires a lot of time, care, and (potentially) lots of money.

How serious is Cushing’s disease in dogs?

Controlling Cushing’s disease is possible if caught early and the tumors are small. Noncancerous tumors can potentially be removed or shrunken with careful treatment and monitoring at the vet’s office. Cushing’s disease caused by an overuse of steroids can be a bit more complicated because you can’t simply stop giving a dog their steroids. If you do, the disease you were initially treating may come back.

However, if a malignant tumor is to blame, the outlook is often poor. Sadly, one in four dogs will develop a form of cancer in their lifetime. Cancers affecting a dog’s endocrine system (the hormonal highway of the body) are difficult to treat, but not impossible. The quality of care you get is within your control so don’t fret until you have to.

Don’t Panic: Dog Insurance Can Help Your Family

Cushing’s disease can be a life-changing, stressful diagnosis for pet parents. Your dog is very ill and the treatment journey can be difficult. Cushing’s disease is a potentially life-threatening prognosis, but you have options for treatment to maintain your family’s quality of life.

If you have dog insurance, you don’t have to compromise on the care your dog receives. Take a moment to figure out how pet insurance works or get started today with a free quote from MetLife Pet Insurance, winner of the Pet Insurance of the Year Award in the 2023 Pet Independent Innovation Awards Program.