Cushing’s Disease in Dogs: Symptoms, Causes & Treatment Guide

Cushing’s disease sneaks up gradually, and most owners first notice the changes during what feels like a normal aging process. If your older dog suddenly starts drinking water like it hasn’t seen any for a week, you’re probably not imagining things — and that sudden shift might be one of the first signs that something’s off under the hood. The good news is that once identified, the condition is manageable with the right approach and close veterinary follow-up.

Most common age: Middle-aged to older dogs · Primary cause: Pituitary-dependent hyperadrenocorticism · Key symptoms: Increased thirst, urination, potbelly · Main treatment: Medication like trilostane · Life expectancy impact: Varies with treatment success

The table below summarizes the key clinical parameters for canine hyperadrenocorticism, drawing from established veterinary sources.

What are the symptoms of Cushing’s in dogs?

Cushing’s disease — technically called hyperadrenocorticism — develops when the adrenal glands overproduce cortisol, the hormone that handles stress response and metabolism. The condition typically creeps in slowly, which is why owners often mistake early signs for normal aging.

The most recognizable early signals involve water consumption and bathroom habits. Dogs with Cushing’s develop polyuria (excessive urination) and polydipsia (excessive thirst), meaning you’ll refill the water bowl far more often than usual. According to VCA Animal Hospitals (specialty veterinary hospital network), affected dogs usually eat more, drink more, and urinate large amounts more frequently than healthy dogs.

What are the early signs of Cushing’s?

• Increased thirst and urination (often the first noticeable change)
• Increased appetite despite potential weight changes
• Panting, even in cool conditions
• Mild lethargy or reduced energy on walks
• Heat sensitivity — seeking cooler spots more than usual

The implication is that these subtle shifts often get attributed to normal senior dog behavior, delaying diagnosis by months.

Symptoms of advanced Cushing’s disease in dogs

As the disease progresses, physical changes become more apparent. A potbellied appearance develops because cortisol redistributes fat to the abdomen while weakening the abdominal muscles. PetMD (veterinary reference publisher) notes that thinning skin, bilateral hair loss (often symmetrical), and muscle weakness become increasingly visible.

The skin changes are particularly characteristic — it becomes fragile and tears easily. Calcium deposits under the skin (calcinosis cutis) may appear as firm, raised patches. Neurological signs like disorientation or circling can emerge if the underlying pituitary tumor grows large enough to press on brain tissue, indicating a poorer prognosis for the animal.

What causes Cushing’s disease in dogs?

The root cause matters because it determines treatment strategy. Roughly 80-90% of canine Cushing’s cases stem from a tumor on the pituitary gland, which then overproduces the hormone ACTH, stimulating both adrenal glands to release excess cortisol, according to Lignans for Life (pet health publisher). This is called pituitary-dependent hyperadrenocorticism (PDH).

The remaining 10-20% of cases originate from a tumor on one of the adrenal glands themselves — adrenal-dependent hyperadrenocorticism (ADH). These adrenal tumors may be benign (adenoma) or malignant (adenocarcinoma), with malignancy rates reported between 15-50% in various studies. A small percentage of cases result from prolonged steroid medication use — called iatrogenic Cushing’s — which suppresses normal adrenal function.

What triggers Cushing’s in dogs?

• Pituitary tumor (85-90% of spontaneous cases)
• Adrenal gland tumor (10-15% of spontaneous cases)
• Long-term corticosteroid medication use
• Age-related hormonal changes in older dogs

What this means is that the majority of cases trace back to a single source — a brain tumor creating a hormone cascade that affects the entire body.

At what age do most dogs get Cushing’s?

Cushing’s typically affects middle-aged to older dogs, with most diagnoses occurring in animals over 7 years old. GoodRx (prescription savings platform) notes that the condition is most commonly identified in senior dogs, often during routine wellness screening that reveals elevated liver enzymes.

While Cushing’s can theoretically affect any breed, some show higher predisposition, including Poodles (especially Miniature Poodles), Dachshunds, Boxers, Boston Terriers, and various Terrier breeds. However, precise breed-specific prevalence data remains limited in veterinary literature.

How common is Cushing’s disease in dogs?

Cushing’s is considered one of the more common feline and canine endocrine disorders. Estimates suggest it affects approximately 1-2% of the overall dog population, though this figure likely underrepresents actual prevalence since many mild cases go undiagnosed. Among dogs presenting to veterinary practices with signs of polyuria/polydipsia, Cushing’s accounts for a significant portion of diagnoses.

How do you treat Cushing’s disease in dogs?

Treatment divides into two main pathways depending on whether the disease is pituitary- or adrenal-dependent. Medical management dominates for pituitary cases, while adrenal tumors may warrant surgical intervention after careful risk assessment.

Cushing’s disease in dogs medication

The two primary medications are trilostane and mitotane. Trilostane (marketed as Vetoryl) works by inhibiting an enzyme needed for cortisol production and has become the preferred first-line option due to its more predictable safety profile, according to the FDA (federal regulatory agency), which notes that treatment requires lifelong management with regular veterinary monitoring and blood tests for dose adjustment.

Mitotane (Lysodren) destroys cortisol-producing cells in the adrenal glands and requires more careful monitoring due to risk of Addison’s disease (adrenal insufficiency). It remains an option but has largely been supplanted by trilostane in current practice.

Surgery and radiation options

Surgical removal of adrenal tumors can be curative if the tumor is benign and has not spread. However, Cornell University College of Veterinary Medicine (academic veterinary institution) reports that adrenal surgery carries a 10-25% mortality risk due to the invasiveness of the procedure and potential for surgical complications.

Radiation therapy for pituitary tumors is available at specialty referral centers but is expensive and not widely accessible. Hypophysectomy (surgical removal of the pituitary tumor) has been performed at university teaching hospitals but remains rare due to technical complexity.

Is it worth it to treat Cushing’s disease in dogs?

This decision depends heavily on quality of life considerations. Cornell Veterinary College reports that dogs receiving medical therapy for PDH survive an average of 2-2.5 years, while untreated dogs may live similar lengths of time but experience significantly poorer quality of life due to progressive symptoms.

Cushing’s disease in dogs test

Diagnosing Cushing’s requires a systematic approach because no single test perfectly identifies the condition. The ACVIM 2012 Consensus Statement on Diagnosis of Spontaneous Canine Hyperadrenocorticism (endocrinology specialty publication) established diagnostic standards that most veterinarians follow today.

Diagnosis process

Initial screening typically begins with basic blood work and urinalysis. VCA Animal Hospitals (specialty veterinary network) notes that elevated liver enzymes — particularly serum alkaline phosphatase (S-ALP) — flag concern, as this enzyme increases directly with cortisol levels in dogs. Additional findings often include elevated glucose, cholesterol, and lipids alongside dilute urine.

Confirmatory testing options

Two main confirmatory tests exist:

• ACTH stimulation test: Blood samples taken before and 1-2 hours after synthetic ACTH injection. Sensitivity ranges from 57-95% depending on the study — per Today’s Veterinary Practice — making it convenient for treatment monitoring but imperfect for initial diagnosis.
• Low-dose dexamethasone suppression test (LDDS): Cortisol samples taken at 0, 4, and 8 hours after dexamethasone injection. Lack of suppression at 8 hours indicates Cushing’s. Higher sensitivity than ACTH stim but requires a full day at the clinic.

Imaging and differentiation

Abdominal ultrasound helps differentiate pituitary- from adrenal-dependent disease by visualizing adrenal gland size, according to Premier Vets (veterinary practice). Both glands enlarged suggests PDH; asymmetric enlargement with one gland much larger points to ADH. Advanced imaging (MRI/CT) may be needed for pituitary tumor characterization at referral centers.

The AAHA 2023 Guidelines (veterinary association) caution that all tests carry limitations — false positives can occur with concurrent illness, and results must be interpreted alongside clinical signs rather than treated as absolute.

What is the life expectancy of a dog with Cushing’s disease?

Survival times vary considerably based on the type of Cushing’s, treatment approach, and how early the condition is caught. The American Kennel Club (breed registry and information source) reports that average survival time for treated dogs is approximately two years, with only 10% living beyond the four-year mark.

Quality of life factors

Life expectancy numbers don’t capture quality of life, which is ultimately what matters most. Cornell Veterinary College distinguishes that treated dogs with PDH survive 2-2.5 years on medical therapy, while adrenal surgery patients may survive 1.5-4 years depending on surgical success and tumor type. Adrenal-dependent dogs on medical therapy alone reportedly survive approximately 15 months — shorter than PDH managed with medications.

Factors that reduce quality of life include secondary complications like diabetes mellitus (which some Cushing’s dogs develop), recurrent skin and urinary infections, worsening muscle weakness, and neurological symptoms if the pituitary tumor grows. Elderly dogs over 10 years face additional challenges from comorbidities like arthritis and kidney disease.

Are dogs in pain with Cushing’s disease?

Cushing’s itself is not typically a directly painful condition. The discomfort comes from secondary effects: the weakness and skin fragility make dogs more prone to injuries, the susceptibility to infections causes inflammation, and the potbellied posture puts strain on the spine and joints. Most dogs with well-managed Cushing’s can live comfortably for months to years.

When to euthanize a dog with Cushing’s

This is never an easy decision, but certain signs indicate quality of life has declined beyond what treatment can meaningfully restore:

• Neurological symptoms (disorientation, circling, seizures) suggesting pituitary tumor progression
• Multiple secondary conditions that require constant management
• Loss of appetite and inability to maintain weight despite treatment
• Incontinence that does not respond to medication adjustments
• Extreme weakness preventing basic mobility
• Recurrent infections that respond poorly to treatment

The catch is that advanced neurological signs from pituitary tumor growth often signal rapid deterioration — owners may need to prepare for end-of-life decisions sooner than expected.

Treatment steps for Cushing’s disease in dogs

Following a confirmed diagnosis, treatment typically progresses through defined stages with careful monitoring at each step.

1. Initial veterinary consultation: Discuss test results and treatment options. For PDH, medication is usually the path forward. For adrenal tumors, evaluate surgical candidacy against overall health.
2. Medication initiation: Begin trilostane or mitotane at calculated starting dose. Trilostane is typically dosed once or twice daily with food.
3. First recheck (10-14 days): ACTH stimulation test to assess initial response and identify any dogs at risk of over-treatment. Dose adjustment is common at this stage.
4. Ongoing monitoring (every 3-6 months): Regular blood work and ACTH stim tests to ensure cortisol levels remain in the therapeutic range. Dose changes may be needed as the disease or dog’s condition evolves.
5. Quality of life reassessment: At each visit, evaluate energy level, appetite, bathroom habits, skin condition, and mobility. These subjective assessments guide continued treatment intensity.
6. Palliative transition (when indicated): If quality of life declines despite optimized treatment, shift toward comfort-focused care including pain management, appetite stimulants, and environmental accommodations.

The implication is that treatment is an ongoing partnership between owner and veterinarian — not a one-time intervention but a sustained commitment to monitoring and adjustment.

“It’s important for a veterinarian to see the dog regularly and do blood tests,” notes an FDA consumer update, emphasizing that dose adjustments are expected as treatment progresses.

“Early diagnosis and management are crucial to extending lifespan,” according to pet health educational sources, reinforcing that the timing of intervention directly impacts outcomes.

The pattern is clear across multiple sources: treatment unlocks better days, not necessarily more days. PetMD reports survival ranges of 1-5 years depending on treatment response, while GoodRx places the average treated survival closer to 1.5 years — variation that reflects differences in when diagnosis occurs, which dogs owners choose to treat, and what complications emerge.

For dog owners facing this diagnosis, the practical choice comes down to weighing medication costs and veterinary visits against what you’ll gain: a dog that’s more comfortable, more active, and more present. Younger, healthier dogs diagnosed early often get the most benefit. Senior dogs with multiple health issues face a harder calculation.

The Today’s Veterinary Practice journal emphasizes that all diagnostic tests carry inherent limitations — false positives occur with concurrent illness, and results should never override clinical judgment. This means your relationship with a veterinarian who knows your dog over time often matters more than any single test result.

Related reading: Cancer Lymph Nodes in Neck: Symptoms, Stages, Treatment

Owners spotting signs like excessive thirst in their dogs can benefit from exploring detailed Cushings treatment guide alongside veterinary advice for effective management.

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