Dog Cushing's Disease (Hyperadrenocorticism): Symptoms, Testing & Trilostane Treatment
Published: 2026-05-31 · Updated: 2026-05-31
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
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.