Cushing’s Disease in Dogs (October 2026) Complete Owner’s Guide

If your vet just mentioned Cushing’s disease, you probably have a hundred questions running through your head. Take a breath. Cushing’s disease in dogs, also called hyperadrenocorticism, is a condition where the adrenal glands produce too much cortisol — the body’s main stress hormone. It sounds scary, and a diagnosis can feel overwhelming, but many dogs live comfortable, happy lives with proper treatment.

I have spent years researching canine health conditions, and I know how much a diagnosis like this weighs on a dog owner. This guide covers everything you need to know: what Cushing’s disease is, what causes it, the symptoms to watch for, how your vet will diagnose it, and every treatment option available in 2026.

Whether your dog was just diagnosed or you are trying to figure out if something seems off, this article walks you through each step with clear, honest information — no medical jargon without explanation, no scare tactics, just the facts you need to help your dog.

What Is Cushing’s Disease in Dogs?

Cushing’s disease in dogs is an endocrine disorder where the body chronically produces more cortisol than it needs. Cortisol is not a bad thing on its own. In healthy amounts, it helps regulate metabolism, manage stress responses, control blood sugar, reduce inflammation, and support immune function. But when cortisol levels stay elevated for too long, the hormone that normally protects the body starts to damage it instead.

Think of cortisol like a fire alarm. It is supposed to ring during emergencies and then shut off. With Cushing’s disease, that alarm keeps blaring day and night, wearing down nearly every system in your dog’s body over time.

The medical term for this condition is hyperadrenocorticism — literally meaning “over-active adrenal cortex.” The adrenal glands, two small organs sitting right above the kidneys, are responsible for the excess cortisol production. Depending on what is triggering the overproduction, the disease falls into different categories, which we will break down shortly.

Cushing’s syndrome is the broader umbrella term. Cushing’s disease specifically refers to the pituitary-dependent form, which accounts for the majority of cases. Most vets and owners use the terms interchangeably in conversation.

Who Gets Cushing’s Disease?

This condition almost always shows up in middle-aged and older dogs. The average age at diagnosis is around 9 to 11 years, though some dogs develop it earlier. While any breed can be affected, certain breeds show a higher predisposition:

• Poodles (especially Miniature and Standard)
• Dachshunds
• Terrier breeds (Yorkshire, Boston, Staffordshire)
• Boxers
• Beagles
• Miniature Schnauzers
• Australian Shepherds

Small breeds tend to develop the pituitary form more frequently, while larger breeds have a slightly higher rate of adrenal tumors. Female dogs are also slightly more prone to the condition than males, though the difference is not dramatic.

What Causes Cushing’s Disease in Dogs

There are three distinct causes of Cushing’s disease in dogs, and understanding which one your dog has makes a big difference in treatment choices. Each type has a different origin, a different prognosis, and sometimes a completely different approach to management.

Pituitary-Dependent Hyperadrenocorticism (PDH)

This is by far the most common form, responsible for about 80 to 85 percent of all Cushing’s cases. A small, usually benign tumor forms on the pituitary gland — a pea-sized organ at the base of the brain. That tumor produces excess adrenocorticotropic hormone (ACTH), which signals the adrenal glands to pump out too much cortisol.

In most cases, these pituitary tumors are tiny, measured in millimeters, and grow very slowly. They rarely spread or cause neurological problems. However, in a small percentage of dogs, the tumor grows large enough to press on surrounding brain tissue, which can cause additional neurological symptoms like circling, seizures, or behavior changes.

Both adrenal glands typically enlarge in response to the constant ACTH stimulation. That is why treating PDH usually focuses on controlling the adrenal glands’ output rather than removing the pituitary tumor itself.

Adrenal-Dependent Hyperadrenocorticism (ADH)

Adrenal-dependent Cushing’s accounts for about 15 to 20 percent of cases. In this form, a tumor grows directly on one of the adrenal glands, causing that single gland to overproduce cortisol regardless of what the pituitary is telling it to do.

Adrenal tumors present a different challenge than pituitary ones. Roughly half of adrenal tumors are benign (adenomas) and half are malignant (carcinomas). Malignant tumors can spread to other organs and are more aggressive. The good news is that if the tumor has not spread, surgical removal of the affected adrenal gland can sometimes be curative.

Because only one gland is involved, the other adrenal gland often shrinks from lack of stimulation. After surgery, the remaining gland needs time to recover normal function, which requires temporary medication support.

Iatrogenic Cushing’s Disease

This third type is different from the other two because it is caused by external medications, not by tumors. When dogs receive high doses of corticosteroid medications (like prednisone, dexamethasone, or prednisolone) over long periods, their body develops the same symptoms as naturally occurring Cushing’s disease.

These medications are commonly prescribed for allergies, autoimmune conditions, arthritis, and inflammatory bowel disease. The body’s own adrenal glands actually shut down cortisol production in response to the external steroids, which means stopping the medication suddenly can cause a dangerous adrenal crisis.

Iatrogenic Cushing’s is usually reversible. Your vet will gradually taper the steroid medication over weeks or months, allowing the adrenal glands to resume normal production. This process requires careful monitoring, but most dogs recover fully.

Signs and Symptoms of Cushing’s Disease in Dogs

Recognizing Cushing’s disease in dogs can be tricky. The symptoms develop gradually, and many owners initially write them off as normal aging. Forum discussions on this topic are filled with owners who say, “I just thought my dog was getting old.” That confusion is one of the biggest reasons the disease goes undiagnosed for months, sometimes years.

Here is the thing: these symptoms are not normal aging. If you notice several of them appearing together, it is worth having a serious conversation with your veterinarian.

Early Symptoms (Often Overlooked)

The first signs are usually subtle and easy to dismiss. Based on real owner reports from discussion forums, excessive thirst and increased urination are the two symptoms most commonly noticed first. You might find yourself filling the water bowl far more often than usual, or your previously house-trained dog starts having accidents indoors.

• Increased water consumption (polydipsia) — drinking far more than usual
• Increased urination (polyuria) — needing to go out more frequently, sometimes having accidents
• Increased appetite — your dog seems constantly hungry, even counter-surfing or stealing food
• Mild panting — more than what the temperature or activity level would explain

Progressive Symptoms

As the disease progresses, the physical and behavioral changes become harder to ignore:

• A distended, “pot-bellied” abdomen caused by fat redistribution and weakened abdominal muscles
• Thin, fragile skin that bruises easily and heals slowly
• Bilateral hair loss (alopecia) along the flanks, belly, and back — often symmetrical
• Recurring skin infections that take longer than expected to clear up
• Noticeable muscle wasting, especially along the back and hind legs
• Persistent panting, even at rest
• Weight gain despite no change in diet (or paradoxical weight loss in advanced stages)
• Lethargy and decreased willingness to exercise or play

Back Leg Weakness

Many owners specifically notice weakness in the back legs. Dogs may struggle to jump onto furniture, have difficulty climbing stairs, or develop a shuffling gait. This happens because excess cortisol breaks down muscle tissue, and the hindquarters are often the first area affected. If your senior dog’s back legs seem to be giving out, do not assume it is just arthritis — especially if other symptoms on this list are present.

Cushing’s Disease vs. Normal Aging

One of the biggest questions owners struggle with is whether what they are seeing is just their dog getting older. Here is a simple way to think about it: normal aging happens slowly and steadily. Cushing’s disease causes a cluster of symptoms that appear and worsen together over a relatively short period (weeks to months).

If your dog suddenly needs water refills twice as often, is having accidents, has a visibly rounded belly, and is losing hair — that combination is not typical aging. A single symptom in isolation might not mean much, but several showing up at the same time warrants a vet visit.

How Is Cushing’s Disease Diagnosed in Dogs

Diagnosing Cushing’s disease is not a quick process. It usually involves multiple tests over several vet visits, which can be frustrating and stressful for both you and your dog. Knowing what to expect ahead of time helps take some of the anxiety out of the process.

Initial Screening Tests

Your vet will start with a thorough physical exam and a detailed history of the symptoms you have noticed. Blood work and urinalysis come next. Dogs with Cushing’s often show specific patterns on routine blood panels:

• Elevated alkaline phosphatase (ALP) — this liver enzyme is high in roughly 90 percent of Cushing’s cases
• Elevated cholesterol and blood glucose levels
• Dilute urine with a low specific gravity
• Possible urinary tract infections (Cushing’s suppresses the immune system, making infections more likely)

These results suggest Cushing’s but do not confirm it. That is where specific diagnostic tests come in.

ACTH Stimulation Test

This is the most commonly used confirmatory test. Your vet will draw blood, inject a synthetic form of ACTH, and draw blood again about one to two hours later. In a healthy dog, cortisol rises modestly and then returns to normal. In a dog with Cushing’s, cortisol spikes dramatically and stays elevated.

The ACTH stimulation test takes several hours to complete. Owners on forums often describe it as stressful because it requires waiting at the clinic, but most dogs tolerate it well. This test is also used later to monitor how well treatment is working.

Low-Dose Dexamethasone Suppression Test (LDDS)

This test works differently. Your vet gives a small dose of dexamethasone (a synthetic steroid), which should suppress cortisol production in a healthy dog. Blood is drawn at baseline, 4 hours, and 8 hours. Dogs with Cushing’s fail to suppress cortisol adequately, meaning levels remain too high throughout the test.

The LDDS test takes about 8 hours, making it a long day at the vet for your dog. It is more sensitive than the ACTH test but can produce false positives in dogs that are stressed or have other illnesses.

Imaging and Additional Tests

Once Cushing’s is confirmed, your vet may order an abdominal ultrasound to check the size and shape of the adrenal glands. This helps distinguish between pituitary-dependent and adrenal-dependent forms. Enlarged adrenal glands on both sides point toward PDH, while an enlarged gland on one side with a shrunken gland on the other suggests ADH.

In some cases, a high-dose dexamethasone suppression test or endogenous ACTH measurement helps further differentiate between the types. Advanced imaging like a CT scan or MRI may be recommended if a pituitary macrotumor is suspected.

Treatment Options for Cushing’s Disease in Dogs

Treatment for Cushing’s disease in dogs depends on the type, the severity of symptoms, your dog’s overall health, and sometimes your budget. There is no single right answer for every dog, and your veterinarian will help you weigh the options. Here is what is available in 2026.

Medication: The Most Common Approach

For the vast majority of dogs with pituitary-dependent Cushing’s, daily medication is the standard treatment. Medication does not cure the disease — it manages the symptoms by controlling cortisol production. Two main drugs are used:

Trilostane (brand name Vetoryl) is the most widely prescribed medication and is generally considered the first-line treatment. It works by blocking an enzyme needed for cortisol production, effectively reducing how much cortisol the adrenal glands release. Most dogs take it once or twice daily with food.

Improvement is usually noticeable within a few weeks. Owners report that thirst and urination decrease first, followed by gradual improvements in energy, skin, and body condition. Regular blood work is required to monitor cortisol levels and adjust the dosage.

Mitotane (brand name Lysodren) is an older medication that works by actually destroying part of the adrenal cortex. It was the standard treatment before trilostane became available. It can be effective but carries a higher risk of causing cortisol levels to drop too low (Addisonian crisis), which is a medical emergency. Your vet will monitor your dog closely during initial treatment.

Other Medications

Several other medications may be considered in specific situations:

• Selegiline (Anipryl) — approved only for pituitary-dependent Cushing’s, but generally less effective than trilostane
• Ketoconazole — an antifungal that also blocks cortisol production, sometimes used when other medications are not tolerated
• Osilodrostate — a newer medication approved in some countries that works similarly to trilostane

Surgery

For dogs with adrenal-dependent Cushing’s (a tumor on one adrenal gland), surgical removal of the affected gland (adrenalectomy) can be curative. This is a major abdominal surgery, and not every dog is a good candidate. Age, overall health, and whether the tumor has spread all factor into the decision.

After surgery, the remaining adrenal gland needs time to resume normal cortisol production. During this recovery period, your dog may need supplemental steroids until the gland “wakes up.” Most dogs recover well, though the surgery itself carries risks that your veterinary surgeon will discuss with you.

Radiation Therapy

For dogs with large pituitary tumors (macroadenomas) causing neurological symptoms, radiation therapy can shrink the tumor and reduce symptoms. This treatment is typically available at veterinary specialty hospitals and requires multiple sessions. It is not a first-line treatment for most dogs but can be life-changing for those with severe neurological involvement.

Monitoring During Treatment

Regardless of which medication your dog takes, regular monitoring is non-negotiable. Your vet will schedule periodic ACTH stimulation tests to check that cortisol levels are in the target range. Dosages often need adjustment over time.

Watch for signs that cortisol has dropped too low: loss of appetite, vomiting, diarrhea, lethargy, or weakness. Forum discussions highlight that appetite loss after starting medication is one of the most concerning side effects for owners. If you notice any of these signs, contact your vet immediately.

Natural and Supplemental Support

Some owners explore natural options alongside veterinary treatment. Melatonin and flaxseed lignans are the most commonly discussed supplements, with some anecdotal reports of mild symptom improvement. These should never replace prescribed medication, but some vets are open to incorporating them as complementary support. Always discuss any supplements with your veterinarian before giving them to your dog.

Prognosis and Life Expectancy for Dogs With Cushing’s Disease

This is the section every owner searches for, and I want to give you an honest, balanced answer. Life expectancy for dogs with Cushing’s disease depends on several factors: the type of Cushing’s, how early it is caught, your dog’s age and overall health, and how well they respond to treatment.

With Proper Treatment

Dogs with pituitary-dependent Cushing’s who respond well to medication can live comfortably for years after diagnosis. Real owners in support forums report their dogs living 4 to 5 years or more with consistent treatment and monitoring. Some dogs are diagnosed at age 9 or 10 and live well into their mid-teens. The key is regular veterinary care and medication compliance.

For dogs with adrenal tumors that are successfully removed surgically, the prognosis can be even better — the disease may effectively be cured. However, malignant adrenal tumors carry a more guarded outlook and depend on whether the cancer has spread.

Without Treatment

Untreated Cushing’s disease will progressively worsen. Complications can include diabetes mellitus, high blood pressure, blood clots (pulmonary thromboembolism), kidney damage, pancreatitis, and chronic skin infections. These secondary conditions are often what ultimately shorten a dog’s life, not the Cushing’s itself.

Quality of Life

Many owners on forums emphasize that quality of life matters more than the exact number of years. A well-managed Cushing’s dog can enjoy daily walks, playtime, good appetite, and companionship. The disease is manageable. The first few months of adjusting medication are the hardest, but most dogs stabilize and return to a comfortable routine.

Assessing Your Dog’s Quality of Life

Use a simple daily check-in approach. Ask yourself: Is my dog still eating well? Still interested in walks or play? Still interacting with the family? Still able to get around comfortably? If the answer is yes to most of these, treatment is working and your dog is having good days.

The Final Stages

In the final stages of Cushing’s disease, dogs may experience severe muscle wasting, inability to stand or walk, chronic infections that will not resolve, organ failure, or neurological decline from a large pituitary tumor. These are difficult signs to witness.

When to Consider End-of-Life Decisions

This is the conversation no competitor wants to have, but it is the one owners are searching for. There is no single right answer for when to say goodbye. The decision is deeply personal and depends on your dog’s quality of life, not just the length of it.

Signs that quality of life is declining significantly include: refusal to eat for extended periods, inability to stand or walk without assistance, chronic pain that medication cannot manage, loss of interest in surroundings and family, and more bad days than good days over the course of a week or two.

Talk openly with your veterinarian. They can help you assess your dog’s condition objectively and guide you through this decision with compassion. You are not giving up — you are making the hardest, most loving choice a pet owner can make.

Frequently Asked Questions About Cushing’s Disease in Dogs

Moving Forward After a Cushing’s Diagnosis

A Cushing’s disease diagnosis in dogs changes things, but it does not have to mean the end of good times with your companion. With the right treatment plan, regular vet visits, and a watchful eye on symptoms, most dogs go on to enjoy comfortable, active lives for years.

If you suspect something is off with your dog — whether it is the excessive thirst, the pot belly, the hair loss, or just a feeling that something is not right — schedule a vet appointment. Early diagnosis makes a real difference in how well treatment works and how quickly your dog starts feeling better.

You know your dog better than anyone. Trust that instinct, ask your vet questions, and take it one step at a time. You and your dog can handle this together.