Symptoms, Diagnosis & Treatment Guide

If your dog has developed a pot-bellied appearance, seems constantly hungry, or is drinking and urinating far more than usual, you may be dealing with one of the most common endocrine disorders in middle-aged and older dogs. Cushing's disease (hyperadrenocorticism) occurs when a dog's body produces excessive amounts of cortisol — the stress hormone — over a prolonged period. Left untreated, it can lead to diabetes, kidney damage, hypertension, and a significantly reduced quality of life.

Understanding what causes Cushing's disease in dogs is the first step toward getting your pet the right treatment. The condition typically stems from one of three sources: a benign tumor on the pituitary gland (accounting for roughly 80–85% of cases), a tumor on one or both adrenal glands (about 15–20%), or prolonged use of corticosteroid medications (iatrogenic Cushing's). According to the Merck Veterinary Manual, pituitary-dependent hyperadrenocorticism (PDH) is by far the most prevalent form, particularly in small to medium-sized breeds.

This guide breaks down the causes, symptoms, diagnostic process, treatment pathways, and real costs you can expect — so you can walk into your veterinary appointment prepared.

What Is Cushing's Disease in Dogs?

Cushing's disease — formally known as hyperadrenocorticism — is a hormonal disorder in which the adrenal glands (small organs sitting atop each kidney) overproduce cortisol. Cortisol is essential in small amounts: it helps regulate metabolism, reduce inflammation, and manage the stress response. But chronically elevated cortisol levels essentially poison the body from the inside out, breaking down muscle, suppressing the immune system, and disrupting nearly every organ system.

There are three recognized forms:

• Pituitary-Dependent Hyperadrenocorticism (PDH): A benign tumor (adenoma) on the pituitary gland at the base of the brain overproduces adrenocorticotropic hormone (ACTH). This hormone signals the adrenal glands to pump out excess cortisol. PDH accounts for approximately 80–85% of naturally occurring cases.
• Adrenal-Dependent Hyperadrenocorticism (ADH): A tumor on one or both adrenal glands directly produces excess cortisol, bypassing the pituitary's regulatory signals. Roughly 50% of adrenal tumors are malignant (adenocarcinomas), and 50% are benign (adenomas). ADH accounts for 15–20% of cases.
• Iatrogenic Cushing's Disease: Caused by long-term administration of corticosteroid medications (prednisone, dexamethasone, methylprednisolone) used to treat allergies, autoimmune conditions, or inflammatory diseases. This form is fully reversible if the medication is tapered under veterinary supervision.

Cushing's is most commonly diagnosed in dogs aged 6–13 years, with the average age at diagnosis around 10–11 years. It is relatively rare in dogs under 5 years old.

What Are the Symptoms of Cushing's Disease in Dogs?

Cushing's disease is often called a "great imitator" because its symptoms develop gradually and overlap with many other conditions. Many owners don't notice the early signs, attributing them to normal aging. The following checklist organizes symptoms by progression stage to help you recognize the pattern.

What Causes Cushing's Disease in Dogs? Risk Factors & Predispositions

While any dog can develop Cushing's disease, certain factors significantly increase risk. Understanding these helps you and your veterinarian maintain appropriate vigilance.

Which Dog Breeds Are Most Prone to Cushing's Disease?

Based on veterinary epidemiological data referenced by the American Kennel Club and peer-reviewed studies, the following breeds show the highest predisposition:

If your dog belongs to one of these breeds and is over age 6, mention Cushing's screening to your veterinarian during annual wellness exams, even if symptoms are not yet obvious.

How Is Cushing's Disease Diagnosed in Dogs?

Diagnosing Cushing's disease is a multi-step process. No single test provides a definitive answer, and your veterinarian will typically move through a sequence of screening and differentiation tests. Here is what the diagnostic pathway generally looks like:

1. Step 1 — Clinical Suspicion & Initial Bloodwork ($80–$200): Your vet will perform a complete blood count (CBC), serum biochemistry panel, and urinalysis. Findings that raise suspicion include elevated alkaline phosphatase (ALP), elevated ALT, high cholesterol, dilute urine (low specific gravity), and possible urinary tract infection. A "stress leukogram" pattern (elevated neutrophils, low lymphocytes and eosinophils) is also common.
2. Step 2 — Low-Dose Dexamethasone Suppression Test (LDDST) ($150–$300): This is the most commonly used screening test. A baseline blood cortisol level is measured, then a small dose of dexamethasone is injected intravenously. Cortisol levels are rechecked at 4 hours and 8 hours. In a healthy dog, dexamethasone suppresses cortisol production. In a dog with Cushing's, cortisol remains elevated. The LDDST has a sensitivity of approximately 85–95% for PDH but may miss some cases of ADH.
3. Step 3 — ACTH Stimulation Test ($100–$250): Synthetic ACTH is injected and cortisol is measured before and 1 hour after. This test has lower sensitivity for PDH (approximately 60–65%) but is more useful for diagnosing ADH and for monitoring treatment response. It is also the test of choice for suspected iatrogenic Cushing's.
4. Step 4 — High-Dose Dexamethasone Suppression Test (HDDST) ($150–$250): If Cushing's is confirmed, this test helps differentiate PDH from ADH. In PDH, the higher dose of dexamethasone may partially suppress cortisol. In ADH, it typically does not. However, this test is not 100% reliable, and about 20–30% of PDH dogs do not suppress.
5. Step 5 — Endogenous ACTH Level ($80–$150): A blood test measuring the dog's own ACTH production. High levels suggest PDH; low or undetectable levels suggest ADH. Sample handling is critical — the blood must be kept cold and processed quickly.
6. Step 6 — Abdominal Ultrasound ($300–$600): Imaging the adrenal glands directly. In PDH, both adrenal glands are usually normal-sized or mildly enlarged. In ADH, one adrenal gland typically has a visible mass, and the opposite gland is atrophied (shrunken). Ultrasound also helps assess whether an adrenal tumor has invaded nearby blood vessels — critical for surgical planning.
7. Step 7 — Brain MRI or CT (if macroadenoma suspected) ($1,500–$3,000+): If your dog shows neurological symptoms or fails to respond to standard treatment, advanced brain imaging may be recommended to check for a pituitary macroadenoma (tumor larger than 10mm).

Can Cushing's Disease in Dogs Be Cured or Treated?

The answer depends on the type and stage. Here is a detailed comparison of treatment pathways:

Important: Never attempt to adjust or discontinue corticosteroid medications without direct veterinary guidance. Abrupt withdrawal can cause an Addisonian crisis — a life-threatening drop in cortisol and aldosterone leading to shock, collapse, and potentially death.

What Is the Life Expectancy of a Dog With Cushing's Disease?

Prognosis varies significantly based on the type of Cushing's, the stage at diagnosis, and the treatment chosen. Here is a realistic breakdown:

According to studies referenced in the Merck Veterinary Manual, dogs with PDH treated with trilostane have a median survival time of approximately 662 to 917 days (roughly 2–2.5 years), with many dogs exceeding these averages when monitoring is consistent and dosing is well-managed. Untreated Cushing's disease does not typically cause rapid death but leads to progressive deterioration — secondary infections, diabetes, kidney failure, and blood clots that significantly reduce quality of life.

Home Care, Monitoring & Lifestyle Management

Managing Cushing's disease at home is a daily commitment. Here is what you need to know:

Medication Administration

If your dog is on trilostane (Vetoryl®), the medication should be given with food to improve absorption. Consistency in timing matters — give it at roughly the same time(s) each day. If you miss a dose, give it as soon as you remember unless it is close to the next scheduled dose. Never double up.

Monitoring at Home

• Track water intake: Measure how much water your dog drinks per day. A sudden increase or decrease can signal that cortisol levels are shifting. Normal water intake is approximately 50–60 mL per kg of body weight per day. A 20 lb (9 kg) dog should drink roughly 450–540 mL (about 2 cups) daily.
• Monitor appetite and urination: Both should gradually normalize as treatment takes effect. Persistent excessive hunger or accidents may indicate under-dosing.
• Watch for signs of over-suppression (Addisonian crisis): Lethargy, vomiting, diarrhea, weakness, collapse, loss of appetite, or shaking. This is a medical emergency — contact your vet or an emergency clinic immediately.
• Skin and coat: Hair regrowth is slow — expect 3–6 months before you see meaningful improvement. Thin skin and calcinosis cutis may take longer.

Veterinary Monitoring Schedule

After starting trilostane, your vet will typically recheck ACTH stimulation tests at 10–14 days, then 1 month, 3 months, 6 months, and every 3–6 months thereafter. Each recheck visit typically costs $100–$250 including the ACTH stim test. Do not skip these — both under-dosing and over-dosing carry serious risks.

Diet & Exercise

There is no specific "Cushing's diet," but these guidelines help:

• Feed a balanced, AAFCO-approved adult maintenance diet. Moderate protein (20–25% on a dry matter basis), moderate fat, and controlled sodium are generally appropriate.
• If your dog has developed secondary diabetes, your vet may recommend a higher-fiber or prescription diabetic diet.
• Maintain gentle, regular exercise to support muscle tone. Avoid strenuous activity if your dog is showing significant muscle wasting or weakness.
• Ensure constant access to fresh water — never restrict water intake, even if urination is excessive. Restricting water in a Cushing's dog can cause dangerous dehydration.

How Much Does Cushing's Disease Treatment Cost?

Budgeting for Cushing's disease requires understanding both the initial investment and ongoing costs. Here is a realistic breakdown based on 2025–2026 US veterinary pricing:

First-year total (medical management with trilostane): Expect to spend approximately $1,500 to $3,000 including diagnosis, medication, and monitoring visits. Ongoing annual cost: Approximately $1,000 to $2,400 per year for medication and rechecks.

If your dog requires surgery or radiation, first-year costs can exceed $7,000 to $15,000. Pet insurance can significantly offset these costs if enrolled before diagnosis — check whether your policy covers endocrine disorders and whether pre-existing condition exclusions apply.

When to See the Vet: Red Flag Symptoms

Can Cushing's Disease in Dogs Be Prevented?

Unfortunately, naturally occurring Cushing's disease (PDH and ADH) cannot be prevented — pituitary and adrenal tumors arise spontaneously, and no diet, supplement, or lifestyle change has been shown to reduce risk. However, there are two areas where owners can take meaningful action:

• Minimize unnecessary steroid use: Iatrogenic Cushing's is the only preventable form. If your dog is prescribed corticosteroids for allergies, arthritis, or other conditions, discuss the lowest effective dose and shortest possible duration with your veterinarian. Ask about steroid-sparing alternatives such as oclacitinib (Apoquel®), lokivetmab (Cytopoint®), or immunotherapy for allergic skin disease.
• Early detection through routine screening: For breeds at higher risk, request that your veterinarian include a cortisol check or Cushing's screening as part of annual senior wellness bloodwork (recommended annually starting at age 7 for predisposed breeds). Catching Cushing's early — before advanced symptoms like calcinosis cutis or secondary diabetes develop — improves treatment outcomes and quality of life.

Frequently Asked Questions About Cushing's Disease in Dogs

Is Cushing's disease in dogs painful?

Cushing's itself is not typically acutely painful, but the secondary conditions it causes can be uncomfortable or painful. Muscle wasting leads to weakness, thin skin is prone to infections and bruising, calcinosis cutis can cause skin irritation, and secondary arthritis or pancreatitis can cause significant pain. Most dogs with treated Cushing's report improved energy and comfort within weeks of starting medication.

Can I treat my dog's Cushing's disease naturally without medication?

There is no scientifically validated natural or holistic treatment that effectively controls Cushing's disease. Supplements marketed for "adrenal support" (such as melatonin, lignans, or ashwagandha) have not demonstrated reliable cortisol reduction in peer-reviewed veterinary studies. Some owners use melatonin (3–6 mg for dogs over 30 lb, 1.5–3 mg for smaller dogs) as an adjunct to help with hair regrowth and mild cortisol modulation, but it should never replace prescribed trilostane or mitotane. Always discuss any supplements with your veterinarian before starting them.

How quickly will I see improvement after starting treatment?

Most owners notice a reduction in thirst, urination, and appetite within 1–2 weeks of starting trilostane. Panting often improves within the first month. Hair regrowth is the slowest change — expect 3–6 months for visible coat improvement, and in some dogs, the coat may never fully return to its pre-Cushing's condition. Skin thickening and calcinosis cutis may take 6–12 months to improve.

What happens if Cushing's disease is left untreated?

Untreated Cushing's disease is progressive. While it is not immediately fatal, over months to years it leads to serious complications: secondary diabetes mellitus (in approximately 10–20% of untreated dogs), chronic kidney disease, hypertension, recurrent infections, blood clots (pulmonary thromboembolism), and congestive heart failure. Quality of life deteriorates significantly. Treatment is strongly recommended for any dog diagnosed with Cushing's who is otherwise a reasonable candidate for medication.

Can Cushing's disease cause diabetes in dogs?

Yes. Chronic cortisol excess induces insulin resistance, and approximately 10–20% of dogs with Cushing's disease also develop diabetes mellitus. If both conditions are present, treating the Cushing's is essential — uncontrolled cortisol makes diabetic regulation extremely difficult. In some cases, diabetes resolves once cortisol levels are normalized, but many dogs require ongoing insulin therapy.

This article is for informational purposes only and does not replace professional veterinary advice. Always consult your veterinarian for diagnosis, treatment planning, and medication management for your dog's specific condition.