Cushing’s Disease in Dogs: Learn About This Common Canine Condition
Key takeaways:
Cushing’s disease occurs when your dog’s body produces too much cortisol, a natural hormone that helps regulate many of the body’s functions.
Common symptoms of Cushing’s disease in dogs include increased thirst and urination, weight gain, hair loss, extra heat sensitivity, and energy loss.
Treatment for Cushing’s disease depends on the type of disease, but it is often treated using medications that your dog will need to take for the rest of their life.
Cushing’s disease is one of the most common conditions affecting older dogs. In dogs with Cushing’s, the body produces too much cortisol, the natural hormone that helps the body regulate many important functions, like the immune system and metabolism.
If your dog is middle-aged or older, watch for changes in behavior and appearance. Like humans, dogs will naturally slow down as they age. But if your dog gains significant weight, drinks more than usual, or needs to urinate frequently, one potential cause may be Cushing’s disease. The disease is not curable, but it is manageable.
What is Cushing’s disease in dogs?
Cushing’s disease happens when your dog’s adrenal glands don’t work correctly and produce too much cortisol. Cortisol is a natural hormone that helps:
Regulate body weight
Suppress inflammation
Maintain immune function
Regulate the body’s response to stressful situations
Search and compare options
Cushing’s disease is more common in middle-aged and older dogs.
What are the signs of Cushing’s disease in dogs?
Some common symptoms of Cushing’s disease in dogs include:
Extreme thirst
Increased urination
Increased appetite
Lack of energy (lethargy)
Sensitivity to heat
Thinning of the skin
Bruising
Calcium deposits on the skin that appear as small, thickened dots (usually on the abdomen)
What causes Cushing’s disease in dogs?
Cushing’s disease in dogs is caused by a tumor or, in rare cases, from taking steroid medications for a long time. Let’s take a closer look at these causes.
Pituitary gland tumor
A small tumor on the pituitary gland, which is located at the base of the brain, is the most common cause of Cushing’s disease in dogs. Up to 90% of dogs affected by Cushing’s have this type. The tumor can be cancerous or benign (noncancerous).
Adrenal gland tumor
A tumor in one or both adrenal glands, which are located above the kidneys, can cause Cushing’s disease. About 15% of dogs with Cushing’s disease have an adrenal gland tumor. Adrenal gland tumors can be benign (noncancerous) or malignant (cancerous).
Read more like this
Explore these related articles, suggested for readers like you.
If your dog has a benign adrenal tumor, surgical removal of the tumor will often cure this type of Cushing’s disease.
Iatrogenic Cushing’s syndrome
Iatrogenic Cushing’s syndrome is the least common cause of Cushing’s disease in dogs. This type can result from long-term use of oral or injectable steroid medications. Dogs usually show improvement once steroid medications are stopped.
How do you diagnose Cushing’s disease in dogs?
If your veterinarian suspects your dog has Cushing’s, they will take blood and urine samples for testing.
Your vet will primarily examine the cortisol-creatinine ratio in your dog’s urine and pay close attention to high levels of the liver enzyme steroid alkaline phosphatase (S-ALP) in the blood. About 90% of dogs with Cushing’s disease have high S-ALP levels.
Once your vet has determined that your dog likely has Cushing’s disease, further testing is necessary to confirm the type of Cushing’s.
The low-dose dexamethasone suppression test is the most accurate way to confirm that your dog has Cushing’s disease. This test involves giving your dog a low dose of the medication dexamethasone. Dexamethasone is a cortisol-type hormone medication that can help veterinarians see how well your dog’s adrenal glands are working.
Veterinarians will be looking at whether the cortisol level in your dog’s blood decreases 8 hours after starting the test. In healthy dogs, the level of cortisol in their blood will drop after being given the medication. Dogs who have Cushing’s disease due to a tumor will not show a drop in their cortisol levels. This allows your dog’s vet to confirm Cushing’s disease.
Once a diagnosis is made, further testing is done to determine the Cushing’s type and treatment.
How do you treat Cushing’s disease in dogs?
Treatment for Cushing’s disease depends on the type of Cushing’s or the location of the tumor your dog has. Let’s take a closer look.
Pituitary gland tumor
Dogs with Cushing’s disease caused by a pituitary gland tumor are most often treated with two medications: trilostane (Vetoryl) and mitotane (Lysodren).
Trilostane (Vetoryl) is FDA approved for treating Cushing’s disease in dogs. It works by blocking the adrenal glands from producing cortisol. But it should not be used in pregnant dogs or dogs with kidney or liver disease. The most common side effects include decreased appetite, vomiting, and diarrhea.
Mitotane (Lysodren) is an anticancer medication considered safe for treating pituitary-related Cushing’s disease in dogs. In one study, over 80% of dogs treated over 3 months with mitotane had a good or excellent response. Common side effects can include vomiting, diarrhea, and loss of appetite.
Your dog’s veterinarian may also prescribe two other medications for pituitary-related Cushing’s disease. These include selegiline (Anipryl) and ketoconazole (Nizoral). But these two medications aren’t usually the first choice because others work better for most dogs.
Adrenal gland tumor
About 15% of Cushing’s cases in dogs are caused by tumors in one or both adrenal glands. Removal of the adrenal tumors can treat the disease, but this surgery is risky and often not advised. Because of the likelihood of the tumor spreading, adrenal-dependent Cushing’s is usually treated with medication. Trilostane is also used to treat this type of Cushing’s disease.
Iatrogenic Cushing’s disease
This type of Cushing’s syndrome is caused by long-term use of steroid medications, such as prednisone and dexamethasone. Treatment for this type of Cushing’s disease involves gradually stopping the steroid medication your dog takes. If your dog is diagnosed with this type of Cushing’s disease, work with your veterinarian to safely wean your dog off their steroids.
Further treatment may be needed to replace the hormones that undamaged adrenal glands usually produce.
How long will a dog live with Cushing’s disease?
Unfortunately, Cushing’s disease will affect your dog’s life expectancy. All dogs will be different. On average, dogs with Cushing’s disease who get treatment live about 1 ½ years.
Keep in mind that Cushing’s disease is usually diagnosed in older dogs. So many dogs with Cushing’s disease die because of another age-related cause rather than Cushing’s disease itself. And dogs with Cushing’s disease who receive treatment can live a high-quality life.
The bottom line
If your dog displays an increased appetite, drinks more water than they normally do, and urinates more than usual, they could have Cushing’s disease. Cushing’s disease occurs when your dog’s adrenal glands don’t work as well as they should. The condition is usually caused by a pituitary or adrenal gland tumor.
When you notice changes in your dog’s health, schedule a visit with your vet. If your veterinarian thinks your dog has Cushing’s disease, they can run several tests to make a diagnosis. Treatments and medication are available to manage Cushing’s disease. The condition usually requires lifelong management, but your dog can live a quality life with careful monitoring and treatment.
Why trust our experts?
References
American Animal Hospital Association. (2023). Diagnostic testing and monitoring.
Barnes, C., et al. (n.d.). Cushing’s disease in dogs. VCA Animal Hospitals.
Brooks, W. (2021). Dexamethasone (Azium, Voren). Veterinary Partner.
Brooks, W. (2022). Laboratory tests confirming Cushing’s syndrome. Veterinary Partner.
Brooks, W. (2022). Treatment of pituitary form of Cushing’s syndrome. Veterinary Partner.
Brooks, W. (2024). Cushing’s syndrome: Classifying the type. Veterinary Partner.
Brum, D. (n.d.). Canine Cushing’s disease. The MSPCA-Angell.
Collins, B. (n.d.). Cushing’s syndrome. Cornell Richard P. Riney Canine Health Center.
Dechra Veterinary Products. (2024). Vetoryl- trilostane capsule [package insert]. DailyMed.
Gollakner, R. (n.d.). Mitotane. VCA Animal Hospitals.
Greco, D. S., et al. (2018). Disorders of the pituitary gland in dogs. Merck Manual Veterinary Manual.
Grognet, J. (2024). Cushing’s disease in dogs. American Kennel Club.
Huang, H. P., et al. (1999). Iatrogenic hyperadrenocorticism in 28 dogs. Journal of the American Animal Hospital Association.
Kintzer, P. P., et al. (1991). Mitotane (o,p'-DDD) treatment of 200 dogs with pituitary-dependent hyperadrenocorticism. Journal of Veterinary Internal Medicine.
Reusch, C. E. (2002). New treatment options in canine Cushing’s syndrome. Veterinary Information Network.
Sanders, K., et al. (2018). Treating canine Cushing’s syndrome: Current options and future prospects. The Veterinary Journal.
Schofield, I., et al. (2020). Survival analysis of 219 dogs with hyperadrenocorticism attending primary care practice in England. Veterinary Record.
Siak, M. (2018). Non-pruritic alopecia in the dog: Is it always hormonal? Veterinary Information Network.
U.S. Food and Drug Administration. (2023). Treating Cushing’s disease in dogs.
Veterinary Partner. (2018). Cushing’s disease in dogs (hyperadrenocorticism): What is it? Veterinary Information Network.
Weir, M., et al. (n.d.). Steroid treatment - Effects in dogs. VCA Animal Hospitals.
