Dog Cushing's Disease (Hyperadrenocorticism): Symptoms, Testing & Trilostane Treatment
Published: 2026-05-31 · Updated: August 2026
Cushing's disease (hyperadrenocorticism) is caused by chronic overproduction of cortisol — the body's stress hormone. The classic case is a middle-aged to senior dog who drinks and urinates excessively, has developed a pot-bellied appearance, and is losing hair symmetrically....
Behavior Profile
| Behavior Type | Endocrine / Chronic Disease |
|---|---|
| Common Triggers | Pituitary adenoma (85% of cases — microadenoma producing excess ACTH), adrenal tumor (15% — unilateral, may be malignant), iatrogenic (long-term steroid use), middle-aged to senior dogs, small breed predisposition (Poodles, Dachshunds, Terriers) |
| Associated Emotions | Diagnostic frustration, Long-term management, Financial commitment |
Cushing's disease (hyperadrenocorticism) is caused by chronic overproduction of cortisol — the body's stress hormone. The classic case is a middle-aged to senior dog who drinks and urinates excessively, has developed a pot-bellied appearance, and is losing hair symmetrically. Cushing's is one of the most challenging endocrine diagnoses in veterinary medicine — no single test is definitive, false positives are common with non-adrenal illness, and treatment requires lifelong monitoring.
Classic Signs (PU/PD/PP/Potbelly)
- Increased drinking (polydipsia) and urination (polyuria) — often the first sign noticed
- Increased appetite (polyphagia) — may become food-obsessed, counter-surfing, begging
- Pot-bellied abdomen (muscle wasting of abdominal wall + enlarged liver + fat redistribution)
- Bilateral symmetric hair loss (truncal alopecia — spares the head and legs)
- Thin, fragile skin, easy bruising, slow wound healing, calcinosis cutis (calcium deposits in skin — pathognomonic when present)
- Excessive panting, muscle weakness, lethargy, recurrent urinary tract infections
Diagnostic Testing
No test is perfect. Standard workup: ACTH stimulation test (screens for iatrogenic Cushing's and monitors treatment), low-dose dexamethasone suppression test (LDDST — can sometimes differentiate pituitary vs adrenal), and abdominal ultrasound (visualize adrenal glands). False positives occur with ANY significant non-adrenal illness — never test for Cushing's in a sick dog.
Treatment & Cost
Trilostane (Vetoryl) is the standard of care: $80-$200/month depending on dog size. Lifelong monitoring: ACTH stimulation tests at 2 weeks, 4 weeks, 12 weeks after starting, then every 3-6 months ($200-350 each). Annual management cost: $2,000-$5,000. Over-suppression (Addisonian crisis from too much trilostane) is a life-threatening emergency requiring ICU hospitalization — owners must know the signs: vomiting, diarrhea, collapse, and stop medication immediately.
Related Topics
Dog behavior researcher with 10 years of experience working with rescue dogs and studying canine communication. I've volunteered at shelters across three states, rehabbed dozens of anxious and reactive dogs, and helped hundreds of owners understand what their dogs are really saying. My writing combines hands-on training experience with current behavioral science — because good dog ownership starts with understanding how dogs see the world.
From the Author — Marcus Chen
I adopted my first rescue dog, Cooper, when I was 23. He was a border collie mix with more anxiety than I knew how to handle. He'd pace, pant, and hide during thunderstorms. I spent months reading behavioral science papers, consulting trainers, and slowly building his confidence through counter-conditioning. It took two years, but Cooper went from a dog who couldn't be left alone for 10 minutes to one who calmly waited by the door when I grabbed my keys. That experience shaped everything I believe about dog training: patience, consistency, and understanding the underlying emotion behind the behavior. There are no quick fixes, but there are right approaches.
Real Case — From Marcus Chen's Experience
A few years ago, I worked with a family whose Golden Retriever, Buddy, had started resource-guarding his food bowl. They'd tried everything — stern commands, hand-feeding, even changing his diet — but the growling only got worse. When I observed Buddy's behavior, I noticed he wasn't guarding food specifically — he was guarding the location where he'd been startled while eating weeks earlier. We moved his bowl to a quiet corner, added a predictable feeding routine, and practiced 'trade-up' exercises (exchanging a low-value item for a high-value treat). Within a month, the guarding behavior had dropped by 80%. The fix wasn't discipline — it was understanding the root cause.
References & Further Reading
- ASPCA. Common Dog & Cat Behavior Issues. aspca.org/pet-care
- American Animal Hospital Association (AAHA). Pet Behavior Resources. aaha.org
- Journal of Veterinary Behavior (Elsevier). Clinical Applications and Research. sciencedirect.com
- American Veterinary Society of Animal Behavior (AVSAB). Position Statements & Resources. avsab.org
Citations are provided for educational reference. Content is reviewed periodically but does not replace professional veterinary advice. If your pet shows signs of illness, contact a licensed veterinarian immediately.