Cushing Syndrome in Dogs: Signs, Diagnosis and Treatment

Written by Corinne Homer, Copywriter. Reviewed by Dr. Linda Simon MVB MRCVS, Team Vet.

Cushing syndrome in dogs, also called hyperadrenocorticism, happens when the body is exposed to too much cortisol for too long. It is diagnosed most often in middle-aged and senior dogs. The earliest clues are often increased thirst, more urination, a bigger appetite and panting, but those signs overlap with several other conditions.

The UK source behind this guide cites estimates that roughly 1% to 2% of dogs older than eight may develop the condition. The exact frequency varies by study and population, and a percentage cannot diagnose an individual dog. What matters is a consistent change from your dog's normal pattern and a veterinary workup that connects symptoms, routine laboratory findings and endocrine testing.

What is Cushing syndrome in dogs?

Cortisol is a glucocorticoid hormone made by the adrenal glands. In appropriate amounts, it helps regulate metabolism, blood pressure, immune responses and the body's reaction to stress. The pituitary gland in the brain normally releases adrenocorticotropic hormone, or ACTH, which tells the adrenal glands how much cortisol to produce.

With Cushing syndrome, that control system is disrupted or the dog receives glucocorticoid medication for long enough to create similar effects. Chronic cortisol excess changes how the body handles water, protein, fat, glucose, skin repair and infection. It can also contribute to high blood pressure, blood clots, diabetes, urinary infections and muscle weakness.

Cushing disease versus Cushing syndrome

Cushing syndrome is the umbrella term for clinical illness caused by excess glucocorticoid exposure. Cushing disease more specifically describes pituitary-dependent hyperadrenocorticism, where an ACTH-secreting pituitary tumor overstimulates both adrenal glands. People often use the terms interchangeably, but the distinction matters because the cause helps determine treatment and monitoring.

Three main types in dogs

1. Pituitary-dependent hyperadrenocorticism: the most common spontaneous form. A pituitary tumor releases excessive ACTH, which drives the adrenal glands to make too much cortisol.
2. Adrenal-dependent hyperadrenocorticism: a functional tumor in one adrenal gland produces cortisol independently. The other adrenal gland may become smaller because normal ACTH signaling is suppressed.
3. Iatrogenic Cushing syndrome: prolonged glucocorticoid treatment, including oral, injected, topical, ear or eye medication in some cases, creates cortisol-like effects. Never stop a steroid suddenly unless the prescribing veterinarian gives a tapering plan.

Signs and symptoms of Cushing syndrome

Most dogs do not become ill overnight. Owners often notice a cluster of gradual changes:

• Drinking more and emptying the water bowl faster
• Urinating more, asking to go outside overnight or having accidents
• Increased appetite and persistent food seeking
• Panting at rest or lower tolerance for heat
• A rounded or pendulous abdomen
• Loss of muscle over the back and legs
• Thin skin, easy bruising or slow wound healing
• Symmetrical hair thinning on the trunk, often sparing the head and legs
• Darkened skin, blackheads or recurrent skin infection
• Recurrent urinary tract infection, sometimes without obvious urinary discomfort
• Reduced stamina, weakness or reluctance to jump

Increased thirst and urination also occur with diabetes, kidney disease, liver disease, some medications and urinary disease. Hair loss has many causes, including allergy, parasites and thyroid disease. Read our guides to kidney disease in dogs and dry or dull coats, but use them to prepare for a clinic visit rather than to self-diagnose.

Aging or Cushing syndrome?

Normal aging can bring lower stamina, body-composition change and different sleep patterns. It should not be used to explain away marked thirst, frequent accidents, ravenous appetite, rapidly thinning skin, recurrent infection or a new pot-bellied shape. A useful owner record includes how many times the water bowl is refilled, when accidents happen, appetite changes, panting at rest, current medication and dated body photos.

Do not deliberately restrict water to test whether thirst improves. A dog drinking more is responding to a physiologic need and must have access to fresh water unless a veterinarian directs otherwise during a specific test.

What causes Cushing disease?

Pituitary and adrenal tumors usually develop without an action the owner caused. Most pituitary tumors are small, although a larger tumor can sometimes produce neurologic signs such as altered behavior, circling, vision change or seizures. Adrenal tumors can be benign or malignant. Iatrogenic disease is linked to external steroid exposure, but the medication may have been essential for another condition.

Breed associations have been reported in Poodles, Dachshunds, Boxers, Boston Terriers, Beagles and several terriers, yet any breed or mix can be affected. Age and the clinical pattern are more useful than breed alone.

How Cushing syndrome is diagnosed

There is no single perfect test. The veterinarian first considers the history and physical exam, then usually runs a complete blood count, chemistry panel and urinalysis. Common supportive findings can include increased alkaline phosphatase activity, dilute urine, high cholesterol, protein in the urine or evidence of infection. Those changes are not specific enough to diagnose Cushing syndrome by themselves.

When the clinical picture supports testing, the veterinarian may use a low-dose dexamethasone suppression test, an ACTH stimulation test or a urine cortisol-to-creatinine ratio. The Merck Veterinary Manual describes the low-dose dexamethasone suppression test as the screening test of choice in many dogs, while also stressing that test selection and interpretation depend on concurrent illness.

Additional testing may include endogenous ACTH measurement and abdominal ultrasound or CT to distinguish pituitary-dependent from adrenal-dependent disease. Imaging an adrenal mass does not automatically prove that it is functional, and a dog with compatible laboratory changes but no clinical signs should not be treated from one number alone.

Treatment for Cushing syndrome in dogs

Treatment depends on the cause, symptom burden, other diseases and the family's ability to monitor closely. Many pituitary-dependent cases are managed medically. In the United States, the FDA explains that trilostane is approved for both pituitary-dependent and adrenal-dependent Cushing syndrome in dogs. It reduces cortisol production and requires prescription dosing and repeated assessment.

Some adrenal tumors are treated surgically by a specialist. Surgery may be curative when a functional tumor can be completely removed, but adrenalectomy has meaningful anesthetic and surgical risk. Pituitary surgery or radiation may be considered at specialty centers for selected cases, particularly when a larger pituitary tumor causes neurologic signs.

Iatrogenic Cushing syndrome is managed by the veterinarian who prescribed the steroid, often through a slow dose reduction or a change in therapy. Abrupt withdrawal can cause dangerous adrenal insufficiency. Never alter a steroid schedule on the basis of a blog or supplement claim.

Monitoring treatment and urgent side effects

Follow-up is part of treatment, not an optional extra. The clinic may monitor symptoms, electrolytes, kidney and liver values, cortisol response and blood pressure. Owners should track drinking, urination, appetite, energy, vomiting, stool and medication timing.

Call the prescribing veterinarian promptly for poor appetite, vomiting, diarrhea, weakness or unusual lethargy. Collapse, bloody diarrhea, severe weakness or inability to stand is an emergency. These can signal excessive adrenal suppression, electrolyte imbalance or another serious problem. Give only the prescribed amount and tell every clinician and emergency hospital that the dog is receiving trilostane, mitotane or a steroid.

Can Cushing syndrome be prevented?

There is no known way to prevent a spontaneous pituitary or adrenal tumor. Iatrogenic disease risk is managed by using steroids only under veterinary direction, at the lowest effective dose and with scheduled reassessment. Topical and ear medications still count as medications, so provide the veterinarian with a complete list.

Managing a dog with Cushing syndrome at home

• Keep fresh water available and offer more bathroom breaks.
• Give medication at the prescribed time and with food if directed.
• Use a calendar for doses, lab checks and refills.
• Prevent access to trash and manage increased appetite without extra calories.
• Use nonslip rugs, ramps or shorter walks when muscle weakness affects mobility.
• Check thin skin for pressure, friction or slow-healing areas.
• Report urinary odor, accidents, straining or blood because infection may be subtle.
• Maintain gentle activity appropriate for the dog's comfort and cardiovascular health.

Our guide to senior dog age, signs and care can help organize observations. A stable routine supports care, but it does not replace the laboratory monitoring that keeps treatment within a safe range.

Can Cushing disease be cured?

Most pituitary-dependent cases are controlled rather than cured. Clinical signs often improve with well-monitored treatment, and many dogs maintain a good quality of life. A removable adrenal tumor may offer a surgical cure in a selected dog. Iatrogenic disease may improve as steroids are safely tapered, although the underlying condition that required steroid therapy still needs a plan.

How long do dogs live with Cushing syndrome?

The original UK guide notes that some treated dogs live about three to four years after diagnosis. That is not a promise or a deadline. Age at diagnosis, cause, tumor behavior, concurrent disease, treatment response and monitoring all change prognosis. Some dogs live much longer than an individual estimate, while others have serious complications sooner.

Untreated disease can progress and may increase the risk of diabetes, infection, hypertension, blood clots, gallbladder disease and weakness. When treatment is declined, ask the veterinarian for a quality-of-life and comfort-monitoring plan rather than assuming there is nothing useful to do.

Can Cushing syndrome be treated naturally?

No food, herb or over-the-counter supplement has been shown to replace appropriate diagnosis and cortisol-directed treatment. "Adrenal support" claims can be misleading, and some ingredients interact with medication or complicate laboratory interpretation. Bring the actual label and dose of every supplement to the veterinarian.

What food is best for a dog with Cushing syndrome?

There is no universal Cushing diet. Choose a complete and balanced food appropriate for the dog's life stage and medical needs, then let the veterinary team adjust calories and nutrients for body condition, muscle loss, high blood lipids, diabetes, kidney disease, urinary issues or pancreatitis risk. A ravenous appetite does not always mean the dog needs more energy.

Measure meals, count treats and use part of the normal ration for training. Avoid a sudden diet change during diagnostic testing or medication adjustment unless the clinic recommends it. The dog feeding guide explains portion and body-condition checks.

Dental comfort, skin infection and muscle weakness can affect how a dog eats. Report chewing difficulty or appetite loss instead of hiding medication in an unlimited amount of rich food. A nutrition plan supports the whole dog, but it cannot normalize cortisol on its own.

Frequently asked questions

What are the first signs of Cushing syndrome in dogs?

Increased thirst, urination, appetite and panting are common early clues. A pattern of change matters more than any single sign.

Is a pot belly always Cushing syndrome?

No. Weight gain, pregnancy, fluid, organ enlargement and other conditions can change abdominal shape. A veterinarian must evaluate the cause.

Can I stop my dog's steroid if I suspect Cushing syndrome?

No. Sudden steroid withdrawal can be dangerous. Contact the prescribing veterinarian for a supervised plan.

Does treatment require blood tests?

Yes. Symptoms and laboratory monitoring help the veterinarian choose and adjust treatment safely.

Can supplements cure Cushing syndrome?

No supplement has been shown to cure pituitary-, adrenal- or medication-dependent Cushing syndrome.