Symptoms, Diagnosis & Treatment Guide

What Is Canine Cushing's Disease?

Canine Cushing's disease, also known as hyperadrenocorticism (HAC), is an endocrine disorder where the adrenal glands produce excessive cortisol over a sustained period. Cortisol is a steroid hormone critical for stress response, metabolism, and immune function — but chronically elevated levels cause widespread damage to organs, skin, muscles, and the immune system.

According to the Merck Veterinary Manual, Cushing's disease affects approximately 1 to 2 dogs per 1,000 annually, making it one of the most commonly diagnosed endocrine disorders in middle-aged and older dogs. Roughly 80–85% of cases are pituitary-dependent (PDH), caused by a benign tumor on the pituitary gland that overstimulates cortisol production. The remaining 15–20% are adrenal-dependent (ADH), caused by a tumor on one or both adrenal glands. A third form — iatrogenic Cushing's — results from prolonged corticosteroid medication use.

Recognizing the Symptoms: Early Warning Signs vs. Advanced Disease

Cushing's disease develops gradually, and early symptoms are easy to dismiss as normal aging. The challenge for dog owners is that no single symptom is pathognomonic (uniquely diagnostic) — but clusters of symptoms should prompt veterinary evaluation. Below is a severity-organized checklist to help you monitor your dog.

Early Warning Signs (Often Overlooked)	Moderate / Progressive Signs	Advanced / Severe Symptoms
Increased water consumption (polydipsia) — drinking noticeably more, emptying bowls faster	Pot-bellied or distended abdomen from muscle wasting and fat redistribution	Recurrent infections (skin, urinary tract, ears) due to immune suppression
Increased urination (polyuria) — more frequent outdoor breaks, indoor accidents in house-trained dogs	Bilateral symmetrical hair loss (alopecia), typically on the trunk, sparing head and legs	Lethargy and muscle weakness — difficulty climbing stairs, jumping, or rising
Increased appetite (polyphagia) — begging more, scavenging, seeming insatiable	Thin, fragile skin that bruises easily or tears with minor trauma	Calcium deposits in skin (calcinosis cutis) — hard, gritty patches
Mild panting more than usual, especially at rest	Darkened or hyperpigmented skin patches on the abdomen	Neurological signs (if pituitary macrotumor): disorientation, head pressing, seizures, circling
Slightly reduced energy during walks or play	Muscle wasting visible along the spine and hindquarters	Pulmonary thromboembolism (blood clots in lungs): sudden collapse, labored breathing — this is an emergency

Important: If your dog shows two or more symptoms from the early column, or any symptom from the moderate or advanced columns, schedule a veterinary appointment. Only a veterinarian can confirm Cushing's disease through specific diagnostic testing.

How Is Canine Cushing's Diagnosed?

Diagnosing Cushing's disease is one of the more complex workups in veterinary endocrinology. No single test is perfect, and your veterinarian will typically run a series of tests to confirm the diagnosis and determine whether it's pituitary-dependent or adrenal-dependent — because the treatment differs significantly.

Total diagnostic cost range: Expect to spend $400–$1,200 for initial diagnosis (Steps 1–3) in a general practice setting. If advanced imaging is needed, total costs can reach $2,000–$3,500. Specialty and university veterinary hospitals will be at the higher end of these ranges.

Treatment Options: Medical, Surgical, and Supportive Care

Once your veterinarian confirms the type of Cushing's disease, the treatment plan will depend on whether it's pituitary-dependent or adrenal-dependent, the severity of symptoms, your dog's overall health, and your budget. Always consult your veterinarian before starting or changing any treatment.

Treatment	Type Used For	How It Works	Success Rate	Monthly Cost
Trilostane (Vetoryl®)	PDH and ADH (most common first-line)	Inhibits cortisol synthesis in the adrenal glands by blocking the enzyme 3β-hydroxysteroid dehydrogenase	80–86% clinical improvement within 2–4 weeks	$60–$200/month depending on dog size and dose
Mitotane (Lysodren®)	PDH (older protocol, still used)	Selectively destroys the cortisol-producing layer of the adrenal cortex	80–90% response; requires careful induction phase monitoring	$30–$80/month (less expensive than trilostane)
Adrenalectomy (surgical removal)	ADH with benign, unilateral tumor	Surgically removes the affected adrenal gland; potential cure if tumor is benign and hasn't metastasized	Curative in 70–85% of benign ADH cases; perioperative mortality ~5–10%	$3,000–$7,000 one-time (surgery + hospitalization)
Radiation therapy	PDH with pituitary macrotumor	Targets and shrinks the pituitary tumor, reducing ACTH overproduction	Improvement in neurological signs in ~75% of cases; tumor shrinkage over 6–12 months	$3,000–$6,000 one-time course
Supportive / Palliative care	Mild cases, dogs where medication isn't tolerated, or owner-managed cases	Dietary management, melatonin/lignans supplementation, treating secondary infections, monitoring	Does not address the underlying disease; may improve comfort and some symptoms	$20–$60/month

Trilostane (Vetoryl®): The Current Standard of Care

Since receiving FDA approval for veterinary use, trilostane has become the first-line treatment for most Cushing's cases. It's administered once or twice daily with food, and the dose is adjusted based on ACTH stimulation test results at 10 days, 30 days, 90 days, and then every 3–6 months for life. Side effects are generally mild (vomiting, lethargy, diarrhea) but can rarely include adrenal insufficiency (Addisonian crisis), which is a medical emergency requiring immediate veterinary attention.

Mitotane (Lysodren®): The Older Protocol

Mitotane involves an initial "induction" phase of daily dosing for 5–10 days until cortisol levels drop, followed by a lifelong "maintenance" phase of 1–2 doses per week. The induction phase requires close observation — if your dog shows vomiting, diarrhea, lethargy, or loss of appetite, you stop the medication and contact your vet immediately. While less expensive than trilostane, mitotane carries a higher risk of adrenal destruction and permanent Addison's disease (hypoadrenocorticism).

Prognosis and Life Expectancy

The prognosis for canine Cushing's disease varies significantly based on the type, stage at diagnosis, and how well the disease responds to treatment. Here's a realistic breakdown:

Scenario	Median Survival Time	Key Factors
PDH treated with trilostane (standard case)	2–2.5 years from diagnosis (many dogs live 3–5+ years with good management)	Regular monitoring, consistent medication, no macrotumor
PDH with pituitary macrotumor	6–18 months without radiation; up to 2+ years with radiation therapy	Neurological symptoms at diagnosis worsen prognosis
ADH with benign tumor, surgically removed	Potential cure; normal life expectancy if surgery is successful	Perioperative complications are the main risk
ADH with malignant tumor (adrenal carcinoma)	6–12 months (metastasis to liver or lungs is common)	Tumor size >5 cm and vascular invasion worsen prognosis
Iatrogenic Cushing's (steroid-induced)	Potentially reversible; gradual steroid taper over weeks to months	Underlying condition requiring steroids may limit prognosis
Untreated Cushing's disease	Progressive decline; death typically from complications (thromboembolism, diabetes, infections, kidney failure)	Quality of life deteriorates significantly without treatment

According to a study published in the Journal of Small Animal Practice, dogs with PDH treated with trilostane had a median survival of approximately 900 days (about 2.5 years), with many dogs living well beyond that with consistent monitoring. The American Kennel Club notes that early diagnosis and treatment compliance are the strongest predictors of a favorable outcome.

Home Care and Daily Management

Managing a dog with Cushing's disease is a long-term commitment, but it's very doable with a consistent routine. Here's what daily life looks like:

Medication Administration

• Trilostane: Give once or twice daily with a full meal (fat helps absorption). Consistency in timing matters — set phone alarms if needed.
• Missed dose protocol: If you miss a dose, give it when you remember if it's within a few hours. If it's close to the next dose, skip it. Never double-dose.
• Storage: Keep trilostane capsules at room temperature, away from moisture. Handle capsules carefully — pregnant women should avoid direct contact with the medication.

Monitoring at Home

• Track water intake: Measure your dog's daily water consumption in cups or mL. A decrease toward normal (roughly 1 oz per pound of body weight per day) is a positive treatment indicator.
• Monitor appetite: Excessive hunger should decrease within 2–4 weeks of effective treatment.
• Watch for Addisonian crisis signs: Vomiting, diarrhea, collapse, severe lethargy, or refusal to eat after starting trilostane or mitotane requires immediate emergency veterinary care. This is caused by over-suppression of cortisol.
• Coat and skin journal: Take monthly photos of your dog's coat from the same angle to track hair regrowth, which can take 3–6 months after cortisol normalizes.

Dietary Considerations

Dogs with Cushing's benefit from a diet that is moderate in fat (12–15% on a dry matter basis), high in digestible protein, and low in sodium. Excess cortisol increases blood pressure and can strain the kidneys, so sodium restriction helps. Avoid high-fat treats, which can exacerbate pancreatitis risk (already elevated in Cushing's dogs). If your dog has concurrent diabetes (seen in roughly 10% of Cushing's cases), your veterinarian will recommend a specific diabetic diet.

Exercise and Lifestyle

Moderate, consistent exercise is beneficial — aim for 20–30 minutes of leash walking twice daily if your dog's mobility allows. Avoid sudden intense exercise, especially in dogs with significant muscle wasting. Provide non-slip surfaces (rugs on hardwood floors) to help dogs with hind-end weakness navigate safely.

The True Cost of Treating Canine Cushing's Disease

Cushing's disease is a chronic condition requiring lifelong management, so understanding the financial commitment is essential before starting treatment. Here's a realistic breakdown based on 2025–2026 U.S. veterinary pricing:

Expense Category	Low Estimate	High Estimate	Frequency
Initial diagnostic workup (blood work, LDDST, ACTH stim, urinalysis)	$400	$1,200	One-time
Abdominal ultrasound	$300	$600	One-time (may repeat annually)
CT/MRI for macrotumor evaluation	$1,200	$2,500	One-time (if indicated)
Trilostane (Vetoryl®) medication	$60/month	$200/month	Ongoing, lifelong
Monitoring ACTH stim tests	$150/test	$300/test	At 10, 30, 90 days, then every 3–6 months
Annual maintenance (medication + monitoring + vet visits)	$1,200/year	$3,600/year	Ongoing
Adrenal surgery (ADH cases)	$3,000	$7,000	One-time
Emergency Addisonian crisis treatment	$800	$2,500	As needed (unpredictable)

First-year total: Most dog owners spend between $1,800 and $4,500 in the first year (diagnosis + medication + initial monitoring). Subsequent years typically cost $1,200–$3,600 annually. Pet insurance can offset a significant portion if your dog was enrolled before diagnosis — check your policy's chronic condition coverage and annual limits.

When to See the Vet Immediately

Can Cushing's Disease in Dogs Be Prevented?

Unfortunately, pituitary-dependent and adrenal-dependent Cushing's disease cannot be prevented — they result from spontaneous tumor development with genetic and age-related risk factors. However, you can take meaningful steps to reduce risk and catch the disease early:

• Avoid unnecessary corticosteroid use: Iatrogenic Cushing's is entirely preventable. If your dog is prescribed prednisone or similar steroids for allergies, arthritis, or other conditions, ask your vet about the lowest effective dose and shortest duration. Discuss steroid-sparing alternatives such as oclacitinib (Apoquel®), lokivetmab (Cytopoint®), or immunotherapy for allergic skin disease.
• Annual senior bloodwork: For dogs over age 7, annual blood panels can catch early biochemical changes (rising ALP, changing cholesterol) before clinical symptoms become obvious.
• Monitor water intake: Keeping a rough log of how much your dog drinks weekly makes it far easier to notice the gradual increase that characterizes early Cushing's.
• Know your breed's risks: If you own a Poodle, Dachshund, Beagle, Boston Terrier, or Yorkshire Terrier, maintain a higher index of suspicion and mention any subtle changes to your vet sooner rather than later.

Frequently Asked Questions

This article is for informational purposes only and does not replace professional veterinary advice. If you suspect your dog has Cushing's disease, consult your veterinarian for proper diagnosis and a treatment plan tailored to your dog's specific needs. For information on veterinary endocrinology specialists in your area, visit the American College of Veterinary Internal Medicine (ACVIM) diplomate directory.