Dog Cushing's Disease: Symptoms, Tests, and Treatment
Cushing's disease (hyperadrenocorticism) makes the adrenal glands churn out too much cortisol — a slow-onset disease most often diagnosed in middle-aged and older dogs. The hallmarks are drinking and peeing more, increased appetite, panting at rest, a pot-bellied appearance, and thinning hair coat. Diagnosis requires specific blood tests (LDDS or ACTH stim); treatment with trilostane is highly effective when started early.
Last reviewed: May 2026
Two Forms — Pituitary and Adrenal
About 80 to 85 percent of canine Cushing's cases are pituitary-dependent — a small benign pituitary tumor signals the adrenal glands to overproduce cortisol. The remaining 15 to 20 percent are adrenal-dependent, where an adrenal-gland tumor itself overproduces cortisol. Both forms are described in detail in the Behrend et al., 2013, JVIM (ACVIM Consensus) on diagnosis and management of canine hyperadrenocorticism.
The Symptoms Owners Notice First
Increased thirst and urination is the single most common owner complaint — accidents in previously house-trained dogs are common. Increased appetite (the dog acts ravenous), panting at rest, a pot-bellied appearance from abdominal-muscle weakness, and a thinning, dull coat (especially on the flanks) round out the classic picture. Many dogs are misdiagnosed as simply 'getting old' for months to years before testing.
Diagnosis: LDDS, ACTH Stim, and Imaging
The two most-used screening tests are the low-dose dexamethasone suppression test (LDDS) and the ACTH stimulation test. LDDS is more sensitive; ACTH stim is more specific but misses some cases. Once diagnosed, abdominal ultrasound distinguishes pituitary from adrenal forms and screens for adrenal tumors. Brain MRI is used when neurological signs (head pressing, behavior change) suggest a large pituitary mass.
Treatment with Trilostane
Trilostane is the first-line oral medication for both forms, given once or twice daily. Doses are individualized by ACTH stim monitoring. Most dogs respond within 4 to 6 weeks — thirst and urination improve first, coat changes take months. Mitotane is an older alternative used in some cases. Surgical removal of an adrenal tumor is curative in selected dogs but is technically demanding and usually referred to a specialist surgeon.
Cost of Diagnosis and Treatment
Initial vet exam costs $50 to $150. Bloodwork and urinalysis add $150 to $300. The LDDS or ACTH stim test runs $200 to $400 plus a $50 to $100 visit fee. Abdominal ultrasound is $300 to $600. Trilostane medication typically costs $40 to $150 a month depending on the dog's weight. Recheck ACTH stim tests every 3 to 6 months add $200 to $400 each. Adrenalectomy surgery is $4,000 to $10,000 at a specialty hospital. Catching Cushing's early on oral medication is dramatically cheaper than treating end-stage complications like diabetes or pulmonary thromboembolism.
When to See a Vet
Call your vet today if:
- Increased thirst and urination over weeks to months
- Increased appetite plus pot-bellied appearance
- Thinning coat or symmetric hair loss on the flanks
- Recurrent skin or urinary infections
- Panting at rest in a dog who didn't used to pant
Go to the ER immediately if:
- Sudden collapse, severe weakness, or pale gums
- Vomiting blood, black tarry stools, or signs of GI ulcer (Cushing's predisposes to GI bleeding)
- Severe respiratory distress in a Cushing's dog (pulmonary thromboembolism is a known complication)
- Seizures or sudden behavior change (large pituitary tumor)
- Suspected adrenal crisis from over-treatment with trilostane (extreme weakness, vomiting, collapse)
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Frequently Asked Questions
Can Cushing's be cured?
Adrenal Cushing's can sometimes be cured by surgical removal of the affected adrenal gland. Pituitary Cushing's is managed but not cured — trilostane controls the cortisol output for most of the dog's remaining life. With treatment, average survival is 2 to 4 years from diagnosis, with quality of life similar to age-matched healthy dogs.
How much does treating Cushing's cost?
Initial diagnostic workup totals $700 to $1,800 with bloodwork, LDDS or ACTH stim, urinalysis, and ultrasound. Trilostane runs $40 to $150 a month long-term. Recheck monitoring tests are $200 to $400 every 3 to 6 months. Total first-year cost is typically $1,500 to $4,000. Adrenalectomy surgery, when appropriate, is $4,000 to $10,000 at a specialty hospital.
Why does my Cushing's dog drink so much water?
High cortisol blocks the kidney's response to antidiuretic hormone, so the kidneys lose excess water and the dog drinks to compensate. Daily water intake can rise from about 20 to 70 mL/kg in a normal dog to 100 to 200 mL/kg in untreated Cushing's. Once trilostane lowers cortisol, drinking normalizes within 2 to 4 weeks.
Are some breeds more prone to Cushing's?
Yes — Poodles, Dachshunds, Boxers, Boston Terriers, Beagles, Yorkshire Terriers, and Staffordshire Terriers are over-represented. Most dogs diagnosed are over 6 years old; average age at diagnosis is 10 to 11 years. Family history isn't usually known but a genetic predisposition is suspected for the pituitary form.
Could my dog's Cushing's actually be from steroid medication?
Yes — iatrogenic Cushing's from prednisone or other long-term steroids causes the same symptoms. The fix is to taper the steroid under your vet's guidance (never stop steroids abruptly). True Cushing's blood tests will look different from iatrogenic Cushing's, so it's important to share all medications with your vet.
Still Not Sure if Your Dog Needs a Vet?
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