Reviewed by Dr. Fiona Lee
Cushing's disease in dogs is serious—it can creep up on your pet so slowly that you might not notice the symptoms right away. But by understanding Cushing's disease, you can learn to recognize the symptoms so you can get your dog treatment and help manage the disease.1
What Is Cushing's Disease?
Cushing's disease (also called hyperadrenocorticism) occurs when your dog's body produces too much cortisol. Cortisol is a natural steroid that helps manage stress, body weight and infections. But when there's too much cortisol, the immune system can actually become weaker and more susceptible to infections.2
Cushing's disease is caused by a small tumor located either on the adrenal gland (adrenal dependent) or on the pituitary gland (pituitary dependent.) About 80% to 85% of cases are pituitary dependent, and only 15% to 20% are adrenal dependent.2
Symptoms of Cushing's Disease
Early detection can make Cushing's more manageable, treat secondary issues faster and improve your dog's quality of life.3 Symptoms may include:4
- Increased thirst (in 80% to 90% of cases)
- Increased urination (in 80% to 90% of cases)
- Excess panting
- Calcification spots on the skin
- Hair loss and thinning skin
- Increased appetite2
- Pot-bellied appearance2
- Lethargy and muscle weakness1
- Frequent skin infections and UTIs5
Causes of Cushing's Disease
Cushing's disease is a complex syndrome. When it's pituitary dependent, the tumor causes the pituitary gland to produce too much adrenocorticotropic hormone (ACTH). This hormone, in turn, stimulates the adrenal glands to produce cortisol. But when it's adrenal dependent, the tumor impacts the adrenal glands directly and causes them to overproduce cortisol.2
Most pituitary tumors are benign. However, about half of adrenal tumors are malignant, and about half could spread to other organs.4
A rarer type of Cushing's may occur in dogs receiving cortisol steroid medications.4
Risk Factors in Cushing's Disease
Middle-aged or senior dogs are at higher risk of Cushing's, but there's no difference in risk between male or female dogs.4
However, a big risk factor is based on dog breed. Breeds at higher risk of the pituitary-dependent form include:4
- Bichon Frise
- Some terrier breeds (Jack Russell, Border, Yorkshire)
- Lhasa Apso
- Miniature Schnauzer
- Miniature Poodle
- Dachshund
In contrast, adrenal-dependent Cushing's is more common in larger breeds, such as:4
- Staffordshire Terrier
- German Shepherd
Breeds at the lowest risk include Labrador Retrievers, Golden Retrievers, Border Collies and Cocker Spaniels.4
Diagnosing Cushing's Disease
Diagnosing Cushing's requires a series of tests to identify how your dog handles cortisol, locate the tumors and rule out other illnesses. Basic tests might include:
- Routine biochemistry profile and blood counts to check for abnormalities associated with Cushing's6
- Ultrasound to detect tumors and rule out cancer and other diseases that mimic symptoms2
- Urinalysis to test for kidney function and UTIs4
- Chest X-ray to screen for cancer4
Your dog may also be given screening tests designed specifically for diagnosing Cushing's, such as:
- Low-dose dexamethasone suppression test (LDDST): Measures how your dog's body regulates cortisol3
- High-dose dexamethasone suppression test (HDDST): Helps determine the type of Cushing's4
- ACTH stimulation test: Checks how the adrenal glands respond to the ACTH hormone3
- Urinary cortisol to creatine ratio (UCCR): A low result means Cushing's is unlikely. False positives are common, so other tests will be needed for confirmation.7
- MRI of your dog's adrenal glands: Effective but expensive1
Treatment Options
Cushing's is best treated with medication or surgery. While these approaches do carry risks, ignoring Cushing's can be life-threatening.1
Medication options for managing Cushing's disease
The most common medications include:
| Drug | How It Works | Side Effects | Notes |
| Trilostane | Stops the adrenal glands from producing cortisol.2 | Vomiting, diarrhea, decreased appetite.4 In rare cases, can lead to adrenal gland destruction and possible death.2 | FDA-approved for both types of Cushing's. Requires close veterinary monitoring.2 |
| Mitotane | Chemotherapy drug that destroys layers of the adrenal gland that produce cortisol.2 | Vomiting, diarrhea, decreased appetite. In rare cases, adrenal gland destruction and possible death.4 | Prescribed off-label and requires close monitoring.2 |
| Selegiline | Efficacy unclear.4 | Vomiting, diarrhea, repetitive movement, fatigue, lack of appetite, trembling. Rare side effects include deafness.8 | FDA-approved for pituitary-dependent type.2 Not often recommended anymore.4 |
| Radiation therapy for the pituitary tumor | May be successful for larger tumors.4 | Has complications common to radiation.4 | Expensive and limited availability.4 |
Dietary adjustments
Along with medication, your veterinarian may recommend dietary adjustments. This will typically be a nutritious diet that is low in fat and has moderate fiber. Look for highly digestible protein and low sodium. Weight management might also need to be part of your dog's diet journey. Ask your veterinarian for suggestions.9
Surgical options
The only way to cure Cushing's is by removing the tumor.2 This may be the primary treatment recommended for adrenal-specific cases,3 especially when the adrenal tumor hasn't spread.2 But the surgery is complex and brings a risk of serious complications such as hemorrhaging or death. The smaller the tumor, the more likely a good outcome.4
Surgery to remove a pituitary tumor is less common.2 About 8% to 20% of dogs die from complications. This surgery is more likely to be successful if the tumor is smaller.10
Natural treatment options
Your veterinarian may recommend natural treatments, especially if your dog has mild adrenal disease. Melatonin, for example, may help keep cortisol levels reduced. When combined with phytoestrogens (like isoflavones, lignans and genistein), it may do a better job of inhibiting the steroids produced by your dog's adrenal glands.11
However, holistic and natural treatments are often best used as an adjunct to conventional treatment for Cushing's, rather than on their own, advises Dr. Jack L. Stephens, founder of Pets Best.
"For my patients, I generally recommend more conventional medicine for Cushing's disease, but sometimes alternative therapies can provide relief for some of the side effects that come with the medications," he says.
Prognosis and Long-Term Management
With close monitoring and the right medication, your dog can have a good prognosis and in some cases start to show improvement in some symptoms within weeks.4
Unless surgery cures the disease, symptoms must be managed with medications for the rest of your dog's life.5 Some dogs respond well to treatment, but continued veterinarian appointments and monitoring are vital. While Cushing's can be managed, without close supervision a dog can relapse or even die from complications.1
Prevention and Early Detection
Unfortunately, most types of Cushing's (adrenal dependent and pituitary dependent) cannot be prevented. Only the iatrogenic type that develops from steroid medicine can be prevented.12
However, catching Cushing's disease early can lead to fewer complications and a better quality of life for your pup. That's because without management, the disease can cause all kinds of secondary issues, like blood clots, UTIs, skin infections, sudden blindness, diabetes and gallbladder disease.4 If the tumor grows and presses on the brain, it can cause neurological issues.10
Treating Cushing's early is vital, but the costs do add up. Diagnosis alone is $500 to $1,500, and surgery could range from $2,500 to $5,000. Medications may cost about $100 a month, but routine blood work and tests may cost $200 to $350 each.13 The earlier your dog starts treatment, the fewer complications they may have. Purchasing pet insurance may help you be proactive so you can make claims for treatment, tests and secondary illnesses and get your pup help right away.
Dogs With Cushing's Disease Can Lead Happy Lives
If your dog is diagnosed with Cushing's, keeping them healthy can be a balancing act. But with frequent veterinarian appointments and the right medication, many dogs can lead happy, fulfilling lives. They'll just need extra care and attention from you as you work closely with your veterinarian to find the best treatment regimen.
Pets Best Can Help You Keep Your Dog Healthy
At Pets Best, our dog insurance plans can be customized for your pet's unique needs. In addition, Pets Best policyholders can speak to a veterinary expert anytime through a 24/7 Pet Helpline.
Pets Best sources/citations
1. "About Cushing's disease in dogs," (1/2021), LakeCross Veterinary, https://www.lakecross.com/site/blog-huntersville-vet/2021/01/28/about-cushings-disease-in-dogs
2. "Treating Cushing's disease in dogs," (6/2023), U.S. Food & Drug Administration, https://www.fda.gov/consumers/consumer-updates/treating-cushings-disease-dogs
3. "A veterinarian's guide to Cushing disease in dogs," Vaughn Fish (n.d.), Belton Veterinary Clinic, https://www.beltonvetclinic.com/services/dogs/blog/veterinarians-guide-cushing-disease-dogs
4. "Cushing's syndrome," Brian Collins (n.d.), Cornell University College of Veterinary Medicine, https://www.vet.cornell.edu/departments-centers-and-institutes/riney-canine-health-center/canine-health-information/cushings-syndrome
5. "Cushing's disease in dogs," Courtney Barnes et al. (n.d.), VCA Animal Hospitals, https://vcahospitals.com/know-your-pet/cushings-disease-in-dogs
6. "Cushing's disease - testing," Malcolm Weir et al. (n.d.), VCA Animal Hospitals, https://vcahospitals.com/know-your-pet/cushings-disease-testing
7. "Urinary cortisol: Creatinine Ratio (UCCR)," (n.d.), Gribbles Veterinary Pathology, https://www.gribblesvets.com.au/veterinarians/our-tests/companion-animals/tests-by-dept/urine/urinary-cortisolcreatinine-ratio-uccr/
8. "Selegiline," Rania Gollakner (n.d.), VCA Animal Hospitals, https://vcahospitals.com/know-your-pet/selegiline
9. "What's the vet-recommended diet for canine Cushing's disease?" Jennifer Coates (2/2024), PetMD, https://www.petmd.com/dog/nutrition/whats-vet-recommended-diet-canine-cushings-disease
10. "Finding a cure for Cushing's disease at WSU," (7/2021), Washington State University, https://news.wsu.edu/news/2021/07/26/finding-cure-cushings-disease-wsu
11. "The troublesome Cushing's syndrome," (4/2023), Animal Health Foundation, https://www.animalhealthfoundation.org/blog/2023/04/the-troublesome-cushings-syndrome/
12. "Cushing's disease in dogs: Symptoms, diagnosis, and management," Brittany Kleszynski (5/2024), https://www.petmd.com/dog/conditions/endocrine/cushings-disease-in-dogs-symptoms-diagnosis
13. "Cushing's disease in dogs: Symptoms and treatments," Aaliyah Pasols (6/2023), Forbes Advisor, https://www.forbes.com/advisor/pet-insurance/pet-care/cushings-disease-in-dogs/