SUMMARY
Addison’s Disease in dogs is a condition in which adrenal glands fail to produce cortisol and aldosterone, causing a hormone deficiency. Its symptoms are very similar to other conditions, earning it the nickname “The Great Pretender.” This guide will walk you through what Addison’s is, signs to watch for, how vets diagnose it, and what long-term management looks like.
The symptoms of Addison’s Disease in dogs mimic the symptoms of many other conditions, like gastrointestinal issues, kidney disease, and general sickness. As a result, a lot of dog owners seek treatment for the wrong condition, and the dog continues to suffer from Addison’s until they finally get tested for it.
As a Veterinarian in Johns Creek, GA, I often have befuddled pet owners come in that will tell me, “He hasn’t really been eating normally. He’ll eat fine for a couple days, then he won’t want to eat for a day or two, then he’s normal again.” Maybe that’s been happening for the past month.
But then you start digging into the history. “Oh yeah, actually, now that you ask, he really hasn’t been eating normally for the past month. It’s been kind of on and off.” You pair that history with a predisposed breed, especially a Poodle, and Addison’s needs to move way up my list.
What is Addison’s Disease in Dogs?
Addison’s Disease, or hypoadrenocorticism, is an endocrine disorder that occurs when adrenal glands are not producing sufficient cortisol and aldosterone. These hormones hold important roles in maintaining a dog’s health, as cortisol handles stress response, metabolism, and immune function, while aldosterone handles electrolyte balance and blood pressure.
There are two main types of Addison’s Disease in dogs. Primary Addison’s is the far more common of the two, while Secondary Addison’s is much rarer.
| Primary Addison’s Disease | Secondary Addison’s Disease | |
|---|---|---|
| Cause | Immune-mediated destruction of adrenal cortex — adrenal glands cannot produce cortisol or aldosterone | Pituitary gland fails to produce sufficient ACTH; most commonly caused by long-term steroid use or pituitary tumour |
| Hormones affected | Both cortisol AND aldosterone deficient | Cortisol deficient only — aldosterone usually preserved |
| Electrolyte abnormalities | Yes — low sodium, high potassium | Usually absent — electrolytes often normal |
| How common | ~95% of cases | ~5% of cases |
| Treatment | Lifelong mineralocorticoid + glucocorticoid replacement | Glucocorticoid replacement only |
| Addisonian crisis risk | High — both hormone systems absent | Lower — aldosterone preserved |
Source: Merck Veterinary Manual — Hypoadrenocorticism in Dogs
Iatrogenic Addison’s is a slightly different version that is caused by long-term steroid use that is stopped abruptly.
It’s important to note that Addison’s is different from Cushing’s Disease, as the latter is caused by the overproduction of cortisol.
Why Is It Called “The Great Pretender”?
Addison’s Disease is known as “The Great Pretender” because its symptoms are so similar to dozens of other conditions, making it hard to diagnose without proper testing.
A lot of times it gets treated as nonspecific GI disease. Vomiting, diarrhea, decreased appetite, lethargy, maybe fever. All these relatively vague symptoms.
You give some supportive medications and expect the dog to get better. But then the medications don’t work. Or maybe they do work temporarily, but a week or two later the dog is back again with lethargy, vomiting, diarrhea, or decreased appetite. That’s when you start thinking, “Huh. That’s interesting. Why does this keep happening?”
Sometimes the primary complaint is really just lethargy, and that can get attributed to all kinds of things, including simply getting older. Because the signs are so nonspecific and can come and go, these dogs can potentially have symptoms for weeks before somebody realizes there’s something more systemic happening.
The waxing and waning pattern of a dog’s condition is one of the telltale signs of Addison’s. We’ll often see dogs improve after receiving supportive IV fluids, as they help correct electrolyte imbalances. But soon after, their condition deteriorates and they’re right back to where they started. This repetitive, episodic pattern is an indicator that a dog should be tested for Addison’s ASAP.
Which Dogs Are Most At-Risk?
All dog breeds are susceptible to Addison’s Disease, but certain breeds, as well as middle-aged and female dogs, are statistically more commonly affected.
| Breed | Notes | Relative Risk |
|---|---|---|
| Standard Poodle | One of the most commonly reported breeds; well-documented genetic predisposition | High |
| Portuguese Water Dog | Strong genetic predisposition; carrier testing available | High |
| Bearded Collie | Frequently reported; immune-mediated form predominates | High |
| Nova Scotia Duck Tolling Retriever | High prevalence in breed health surveys | High |
| West Highland White Terrier | Reported predisposition | Moderate–High |
| Great Dane | Large breed with documented increased risk | Moderate |
| Rottweiler | Moderate representation in published case series | Moderate |
| Soft Coated Wheaten Terrier | Addison’s reported alongside protein-losing conditions | Moderate |
| Mixed breed / any breed | Addison’s can occur in any breed | Lower, but possible |
Sources: Oberbauer AM et al. (2002) J Vet Intern Med; Famula TR et al. (2003) J Small Anim Pract; Shaker EH et al. (1988) J Am Vet Med Assoc.
What Are the Signs of Addison’s Disease in Dogs?
The most common signs of Addison’s Disease in dogs include lethargy, decreased appetite, vomiting, diarrhea, weight loss, and weakness. The fact that these are common symptoms for any number of conditions combined with the waxing and waning pattern of Addison’s symptoms can make this disease hard for pet owners to identify.
| Early / Subtle Signs (chronic Addison’s) |
|---|
| Lethargy and weakness |
| Decreased appetite or intermittent vomiting |
| Weight loss over weeks to months |
| Increased thirst and urination |
| Waxing and waning GI signs (“episodic” illness) |
| Shivering or muscle tremors |
| Depression or seeming “off” |
Source: Merck Veterinary Manual — Hypoadrenocorticism in Dogs
While a dog’s shaking or tremors can be attributed to anxiety or cold, they can be important considerations in context with other signs.
What Is an Addisonian Crisis?
An Addisonian crisis is a life-threatening condition that should be treated as an emergency, and it is the result of a dog that has been undiagnosed with or under-treated for Addison’s Disease whose hormone deficiency has become acutely decompensated. Clinical signs include:
| Addisonian Crisis — Seek Emergency Care Immediately |
|---|
| Collapse or inability to stand |
| Severe vomiting and/or diarrhea |
| Sudden profound weakness |
| Very low blood pressure (pale gums, weak rapid pulse) |
| Severe dehydration |
| Abnormal heart rhythm from high potassium |
| Loss of consciousness |
Source: Merck Veterinary Manual — Hypoadrenocorticism in Dogs
An Addisonian crisis can be scary. These dogs can come in very sick. They may be profoundly weak, dehydrated, collapsed, or even obtunded. And a lot of times, when that dog first comes through the door, you don’t immediately know you’re dealing with an Addisonian crisis. You’re looking at a dog in shock. At that point, the immediate priority isn’t necessarily figuring out the exact diagnosis. The priority is stabilizing the patient.
That’s really how I think about an Addisonian crisis: First, get the dog stable. Then figure out why the dog became unstable and what we need to do to keep it stable.
It can’t be stressed enough how important it is for at-risk breed owners to know the crisis signs to watch for and get Urgent Care in Johns Creek, GA quickly. Prompt emergency intervention can help prevent the condition from becoming fatal.
How Is Addison’s Disease Diagnosed?
Diagnosing Addison’s Disease in dogs involves different lab tests, including blood work and an ACTH stimulation test, the latter of which is the most effective way to confirm Addison’s.
If they’re presenting with fever or lethargy, maybe we start with bloodwork and potentially testing for tick-borne disease depending on the history. If they’re presenting primarily with GI signs, maybe we take radiographs and run bloodwork. We’re initially trying to rule out some of the more obvious things like gastroenteritis, pancreatitis, an obstruction, etc. Then you start seeing things that don’t quite fit.
Blood work on dogs with Addison’s will often show electrolyte imbalances, low sodium, high potassium, and elevated kidney values.
You can see other nonspecific bloodwork changes as well. Albumin can be part of that overall picture, but I wouldn’t call a decreased albumin a dead giveaway. The electrolyte pattern is much more classic.
Ultimately, the gold standard for diagnosing Addison’s disease is an ACTH stimulation test. From the owner and dog’s perspective, it’s actually pretty straightforward. We draw an initial blood sample to measure baseline cortisol. Then we administer synthetic ACTH, which should stimulate the adrenal glands to produce cortisol. We wait about an hour and then collect another blood sample to see how the adrenal glands responded.
That said, we can’t run the ACTH stimulation test if a dog has already been given certain steroids. This is an important bit of information to confirm before treatment in stable patients.
Staying on top of your dog’s Preventive Care in Johns Creek, GA is an effective way to identify Addison’s early, as routine bloodwork can catch the telltale electrolyte changes.
How is Addison’s Disease Treated?
Addison’s Disease in dogs requires lifelong treatment that involves routine hormone replacement therapy to supplement the hormones that the adrenal glands can no longer produce.
Long-term treatment typically focuses on two main hormones:
- Mineralocorticoid: Treated with monthly DOCP injection/daily oral fludrocortisone
- Glucocorticoid: Treated with daily low-dose prednisone
The good news is that if you catch Addison’s early enough and the dog doesn’t have a lot of other significant medical problems, you can generally manage these dogs pretty well. Basically, we need to replace what the body isn’t producing.
That’s where stress dosing comes in. When a dog is sick, undergoing surgery, or experiencing any significant stress, the dog will need an increased dose of prednisone to balance their cortisol levels, as they are unable to mount their own cortisol response.
An Addisonian crisis is treated with IV fluids to restore blood pressure and correct electrolyte imbalances and IV steroids for immediate stabilization.
Day-to-day management may seem like a lot, but with the right plan in place, most dogs with Addison’s can still live normal lives. Schedule some time with us to discuss Wellness Plans in Johns Creek, GA to find a plan right for your dog.
What Is the Long-Term Outlook?
Dogs that develop Addison’s Disease have an excellent prognosis when diagnosed correctly, as dogs that receive proper, consistent treatment often live normal lifespans. Dogs should undergo blood work every 6-12 months to monitor electrolyte levels and adjust medication dosing if needed.
Thankfully, Addison’s is one of the most manageable endocrine disorders in veterinary medicine. However, if left untreated, Addison’s Disease is progressive and eventually fatal. Diagnosing and treating it early makes all the difference.
Frequently Asked Questions
| Question | Answer |
|---|---|
| What presentation makes you think, “This might be Addison’s,” before you even run tests? | This is a tough one because Addison’s can present in so many different ways. Honestly, before I even get into the exam room, if I see that it’s any kind of Poodle or Poodle mix and there’s a history of these waxing and waning symptoms, Addison’s starts creeping onto my radar. The dog presents because he’s vomiting, has diarrhea, and is lethargic. From the owner’s perspective, it looks like an acute problem. They’re thinking, “He probably got into the trash,” or, “He must have eaten something outside.” But then you start digging into the history. “Oh yeah, actually, now that you ask, he really hasn’t been eating normally for the past month. It’s been kind of on and off.” That waxing and waning history is a big clue. The dog gets sick, seems to recover, gets sick again, seems to recover, and eventually comes in because this particular episode is worse than the others. |
| What are some factors that you look at most when diagnosing Addison’s? | One of the classic things we look closely at is the electrolytes. There are really two pieces to Addison’s disease: glucocorticoid deficiency and mineralocorticoid deficiency. The glucocorticoid side basically means the body isn’t producing enough cortisol. These dogs feel terrible because they don’t have an appropriate amount of their naturally occurring steroid hormones. With mineralocorticoid deficiency, the body’s regulation of sodium and potassium becomes abnormal. With classic Addison’s, we commonly see low sodium and high potassium, which results in a decreased sodium-to-potassium ratio. Those electrolyte abnormalities, combined with the history, breed, clinical signs, and other bloodwork findings, can really increase your suspicion for Addison’s. |
| What does an Addisonian Crisis look like? | A dog experiencing an Addisonian Crisis is very sick and often extremely weak and in shock. The first priority is stabilization. We need IV access. We need to start fluid resuscitation. We need to assess perfusion and cardiovascular status and start getting that patient stable. Meanwhile, we’re figuring out what the heck is going on. Is this a heart problem? An abdominal mass? Internal bleeding? Severe GI disease? Addison’s? There are several emergencies that can initially look similar. So those first minutes are really about recognizing, “This dog is unstable and in shock, and I need to do something about that right now.” Then, while we’re stabilizing the patient, we run diagnostics and narrow down the cause. |
Everything to Know About Addison’s
Addison’s Disease in dogs is an extremely treatable condition with a strong prognosis, but its symptoms mimic many other diseases, making it easy to miss. Know the signs, watch for a waxing/waning pattern in your dog’s condition, especially if they’re an at-risk breed, and schedule a Veterinary Appointment in Johns Creek, GA right away for the best results.
Knowing what to watch for and getting prompt, proper treatment can be the difference between a dog that lives with this condition comfortably and one forced to deal with unpleasant symptoms on and off indefinitely.
