Your dog is drinking water like they just ran a marathon, their belly looks bloated, and their coat has gone thin and patchy. Or maybe it's the opposite your dog won't eat, keeps vomiting, and seems weaker every single day. Nobody told you the adrenal glands could be behind both pictures.

Dogs get two main adrenal gland disorders: Cushing's disease (too much cortisol) and Addison's disease (too little cortisol). Cushing's causes increased thirst, urination, hair loss, and a pot-bellied appearance. Addison's causes vomiting, diarrhea, weakness, and can lead to sudden collapse. Both are diagnosed through blood tests and treated with lifelong daily medication.

Key Takeaways

• The adrenal glands sit near the kidneys and produce hormones that control salt balance, metabolism, and the body's stress response.
• Cushing's disease (hyperadrenocorticism) means the adrenal glands make too much cortisol. It mostly affects middle-aged to older dogs.
• Addison's disease (hypoadrenocorticism) means the adrenal glands don't make enough hormones. It mostly affects young to middle-aged dogs.
• Cushing's is usually caused by a tumor in the pituitary gland or the adrenal gland itself. Addison's is usually an autoimmune condition.
• Both conditions are diagnosed with specific blood tests and both need lifelong daily treatment once confirmed.
• An Addisonian crisis is a true medical emergency. A dog that suddenly collapses, especially with a very slow heart rate, needs a vet immediately.

What Do the Adrenal Glands Actually Do?

Your dog has two small adrenal glands, one sitting just in front of each kidney. Each gland has two parts that do very different jobs. The outer part, called the cortex, makes three types of hormones: mineralocorticoids that balance sodium and potassium, glucocorticoids like cortisol that manage metabolism and inflammation, and sex hormones. The inner part, called the medulla, releases adrenaline and noradrenaline, which kick in during stress or low blood sugar to raise heart rate and blood pressure.

Think of the adrenal glands as your dog's internal thermostat and emergency response team combined. When either part malfunctions, the effects show up across the whole body, not just in one organ.

What Causes Cushing's Disease in Dogs?

Cushing's disease, medically called hyperadrenocorticism, happens when your dog's body is exposed to too much cortisol for too long. Most cases (85 to 90 percent) come from a small tumor in the pituitary gland, a pea-sized gland in the brain that signals the adrenal glands to work overtime. A smaller share of cases (10 to 15 percent) come from a tumor directly in the adrenal gland itself. A third type, called iatrogenic Cushing's, happens when a dog has been on long-term steroid medication for another condition, such as allergies or an immune disorder.

Cushing's disease is most common in middle-aged to older dogs, typically between 7 and 12 years. Certain breeds like Poodles, Dachshunds, and Boston Terriers are seen more often, though any dog can develop it.

Signs Your Dog Might Have Cushing's Disease

The classic signs of Cushing's disease build up slowly, which is why many pet parents mistake them for normal aging at first. Watch for:

• Drinking noticeably more water and needing to urinate more often
• A pot-bellied, saggy abdomen appearance
• Hair thinning or loss, especially along the back and belly, without much itching
• Increased appetite
• Thin, fragile skin that bruises or heals slowly
• Panting more than usual, even at rest
• Muscle weakness and reduced stamina on walks

If your dog is drinking so much water they're waking you up at night to go out, or their belly has started looking round and low, that combination is worth a vet visit specifically to ask about Cushing's.

How Is Cushing's Disease Diagnosed?

Diagnosing Cushing's disease can take time because early blood work often looks only mildly abnormal, and other illnesses can produce similar results. Your vet will usually start with routine blood and urine tests, then move to specific hormone tests once Cushing's is suspected. Two tests are commonly used to confirm the diagnosis and figure out whether the cause is a pituitary tumor or an adrenal tumor: the ACTH stimulation test, which measures how the adrenal glands respond to a hormone that should trigger cortisol release, and the low-dose dexamethasone suppression test. Abdominal ultrasound is often added to check the size and shape of both adrenal glands, since this helps tell a pituitary-driven case apart from an adrenal tumor.

How Is Cushing's Disease Treated?

For dogs with the pituitary form of Cushing's, the most commonly used medication is trilostane (brand name Vetoryl), which blocks the enzyme that produces cortisol. It is currently the only drug approved to treat both the pituitary-dependent and adrenal-dependent forms of the disease in dogs. Mitotane is an older alternative that works differently, by directly reducing adrenal tissue, but it tends to carry more side effects. Dogs on trilostane usually start showing improvement in energy and thirst within a few weeks, though coat and skin changes can take several months to fully recover.

If the cause is a tumor confined to one adrenal gland, surgery to remove it can sometimes offer a longer-term fix, though this is major abdominal surgery and not every dog is a good candidate. If iatrogenic Cushing's is the cause, treatment means slowly tapering the steroid dose under close veterinary supervision, since stopping suddenly can be dangerous.

Whichever form your dog has, this is a lifelong condition that needs regular monitoring, not a one-time fix. Bloodwork is repeated periodically to make sure the medication dose is neither too high nor too low.

"The primary goal of treatment is to control clinical signs, including polyuria, polydipsia, and changes in coat, so that pets and families see a genuine improvement in quality of life." — American Animal Hospital Association (AAHA), Selected Endocrinopathies of Dogs and Cats Guidelines

What Causes Addison's Disease in Dogs?

Addison's disease, or hypoadrenocorticism, is essentially the opposite problem. Instead of too much cortisol, the adrenal glands don't produce enough hormones at all. In most dogs, the exact trigger isn't known, but vets believe an autoimmune process is usually responsible the body's own immune system gradually destroys adrenal tissue. Addison's can also develop after certain cancer treatments or medications that damage the adrenal gland, including some of the same drugs used to treat Cushing's disease.

Addison's tends to affect young to middle-aged dogs, and it shows up more often in females. Certain breeds carry a higher genetic risk, including Standard Poodles, West Highland White Terriers, Great Danes, Bearded Collies, Portuguese Water Dogs, and Nova Scotia Duck Tolling Retrievers.

Signs Your Dog Might Have Addison's Disease

This is one of the trickiest conditions in veterinary medicine because its early signs are so vague and can come and go. Vets sometimes call it "the great pretender" because it can look like almost any other illness. Common signs include:

• Repeated episodes of vomiting and diarrhea
• Loss of appetite
• Lethargy and general weakness
• Gradual, sometimes severe, weight loss
• Dehydration
• Occasional shaking or muscle tremors

Because these signs are nonspecific and often improve on their own for a while, many dogs are misdiagnosed with a stomach bug or food sensitivity before Addison's is finally caught, often after a crisis.

What Is an Addisonian Crisis?

An Addisonian crisis is a sudden, severe worsening of Addison's disease, and it is a genuine medical emergency. When the adrenal glands stop producing enough aldosterone, potassium builds up in the blood while sodium drops. High potassium can slow the heart down dramatically some affected dogs have heart rates of 50 beats per minute or lower which can cause sudden weakness, shock, or collapse. Low cortisol at the same time drops blood sugar, adding to the danger.

If your dog collapses, becomes suddenly very weak, or has an unusually slow heartbeat, treat it as an emergency and get to a vet immediately. Dogs in an Addisonian crisis need intravenous fluids right away to stabilize sodium, potassium, and blood sugar levels.

How Is Addison's Disease Diagnosed?

Vets look for a specific pattern on standard bloodwork first: very low sodium alongside very high potassium. This pattern raises suspicion, but it isn't proof on its own, since other conditions can cause it too. The confirming test is the same ACTH stimulation test used for Cushing's, but the result is read the opposite way. In Addison's, baseline cortisol is already low, and it barely rises even after the stimulating hormone is given, showing the adrenal glands simply can't respond.

Some dogs have a milder form called atypical Addison's disease, where cortisol is low but sodium and potassium levels stay normal. This form is easier to miss because the classic blood clues aren't there.

How Is Addison's Disease Treated?

Once a dog is stabilized from a crisis, treatment shifts to lifelong hormone replacement. Most dogs need two types of medication: a mineralocorticoid, usually given as a monthly injection, to replace the hormone that balances sodium and potassium, and a daily oral steroid like prednisone to replace cortisol. Bloodwork is repeated regularly, especially in the first year, to fine-tune the dose for each individual dog.

The encouraging part is that with consistent treatment, most dogs with Addison's disease go on to live a full, normal life. The key is catching it early and never skipping doses, since this hormone deficiency doesn't correct itself.

Cushing's vs Addison's: A Quick Comparison

Are Adrenal Tumors in Dogs Cancerous?

Not always. Adrenal tumors can be benign or malignant, and the type isn't usually known until imaging or surgery. A separate, rarer type of adrenal tumor called a pheochromocytoma develops in the medulla, the part of the gland that produces adrenaline. These tumors often cause no obvious signs and are sometimes found by accident during scans for something else. When signs do appear, they can include increased thirst, a fast heart rate, restlessness, and a swollen abdomen. Treatment usually involves surgery when possible, along with managing blood pressure beforehand.

Living With a Dog on Lifelong Adrenal Medication

Both Cushing's and Addison's require medication for the rest of your dog's life once confirmed. This can feel overwhelming at first, but most families settle into a routine quickly. A few things help:

• Keep a simple daily log of water intake, appetite, and energy so you can spot changes early
• Never stop or adjust medication doses without your vet's guidance, even if your dog seems better
• Stick to follow-up bloodwork schedules, since dosing often needs small adjustments over the first year
• Watch for early signs of both under- and over-treatment, since both cause different symptoms
• Keep your dog's joints and muscles supported, since long-term hormone imbalance often affects mobility and coat quality alongside the core disease

A joint support supplement such as Flexirun Tablet can help maintain mobility in senior dogs already managing an endocrine condition, while a gut-focused option like Synbiotic DC Capsule can support digestion in dogs prone to GI upset, which is common with both Cushing's and Addison's.

FAQ Section

Can a dog live a normal life with Cushing's disease?
Yes. Most dogs with Cushing's disease live comfortably for years with daily trilostane and regular monitoring. Signs like excessive thirst and panting usually improve within weeks, though coat and skin changes take longer. Without treatment, though, Cushing's gradually raises the risk of other problems like diabetes and blood clots, so ongoing veterinary care matters even after your dog seems stable.

Is Addison's disease in dogs curable?
No, Addison's disease is not curable, but it's very manageable. Dogs need lifelong hormone replacement, usually a monthly injection plus a daily steroid tablet, to make up for what their adrenal glands can no longer produce. With consistent treatment and regular bloodwork, dogs with Addison's typically have a normal lifespan and quality of life.

What dog breeds are most at risk for adrenal gland disorders?
For Addison's disease, Standard Poodles, West Highland White Terriers, Great Danes, Bearded Collies, Portuguese Water Dogs, and Nova Scotia Duck Tolling Retrievers carry a higher genetic risk. For Cushing's disease, Poodles, Dachshunds, and Boston Terriers are commonly affected, though the disease can appear in any breed, especially as dogs age past seven.

How can I tell if my dog's excessive thirst is Cushing's disease or something else?
Excessive thirst and urination can point to several conditions, including diabetes, kidney disease, and Cushing's disease. What sets Cushing's apart is the combination of increased thirst with a pot-bellied appearance, hair thinning, and increased appetite. Only bloodwork and hormone testing by your vet can confirm which condition is actually causing the symptoms.

Is Cushing's disease painful for dogs?
Cushing's disease itself doesn't typically cause direct pain, but the muscle weakness, thin skin, and reduced stamina it causes can affect your dog's comfort and quality of life over time. Left untreated for years, it also raises the risk of painful secondary problems like blood clots, high blood pressure, and diabetes.

References

• Bruyette, David. "Disorders of the Adrenal Glands in Dogs." Merck Veterinary Manual, Pet Owner Version. https://www.merckvetmanual.com/dog-owners/hormonal-disorders-of-dogs/disorders-of-the-adrenal-glands-in-dogs
• "Addison Disease (Hypoadrenocorticism) in Animals." Merck Veterinary Manual, Endocrine System. https://www.merckvetmanual.com/endocrine-system/the-adrenal-glands/addison-disease-hypoadrenocorticism-in-animals
• "Cushing's Disease in Dogs." VCA Animal Hospitals. https://vcahospitals.com/know-your-pet/cushings-disease-in-dogs
• "Trilostane." VCA Animal Hospitals. https://vcahospitals.com/know-your-pet/trilostane
• American Animal Hospital Association (AAHA). "Monitoring Strategies for Trilostane Therapy in Dogs With Cushing's Syndrome." https://www.aaha.org/newstat/publications/monitoring-strategies-for-trilostane-therapy-in-dogs-with-cushings-syndrome/
• U.S. Food and Drug Administration. "Treating Cushing's Disease in Dogs." https://www.fda.gov/consumers/consumer-updates/treating-cushings-disease-dogs