Often referred to as “the great pretender,” Addison’s disease has the ability to mimic other common diseases in dogs, which typically presents a challenge when it comes time to diagnose the disease that affects a dog’s adrenal glands.
Also referred to as hypoadrenocorticism, Addison’s disease is uncommon in dogs and rare in humans, and typically occurs when the adrenal glands do not produce enough of the hormone cortisol.
Here’s a look at what causes Addison’s disease, the symptoms and how to treat it.
What Is Addison’s Disease in Dogs?
Addison’s disease is an endocrine disorder that occurs as a result of adrenal gland failure. Most dogs suffering with Addison’s disease are deficient in both adrenal hormones cortisol and aldosterone.
Addison’s disease is most often diagnosed in young to middle-aged dogs, with the most common breeds affected including the standard poodle, Portuguese water dog and Great Dane.
While the direct and primary cause of hypoadrenocorticism is still unknown, most cases are a result of autoimmune disease. In some instances, rapid withdrawal from adrenal suppressive medications (steroids), pituitary surgery and cancer can also result in a deficiency of the adrenocorticotropic hormone (ACTH), according to the American Animal Hospital Association.
Dogs that suffer with Addison’s disease often lack the “ability to fight inflammatory diseases like allergies, asthma and autoimmune disease and find it difficult to properly regulate salt and water balance including sodium and potassium levels that regulate blood pressure, generalized metabolism and stress,” says Dr. Michael Fleck, D.V.M. veterinarian and co-host of the radio show, The Pet Buzz.
What Is the Life Expectancy of Dogs With Addison’s Disease?
Although Addison’s disease is a complicated illness, the proper care and treatment can help dogs diagnosed with the illness live long, happy lives.
“Unrecognized or untreated Addison’s disease impacts an animal’s quality of life and can be life-threatening,” says Dr. Jennifer Sperry, D.V.M., veterinary advisor for Pets Plus Us, a pet insurance company in Canada.
If left untreated, Addison’s disease is potentially fatal and can cause a variety of harmful symptoms in dogs.
Symptoms and Behaviors of Dogs With Addison’s Disease
Unfortunately for their owners, dogs with Addison’s disease often display vague signs and symptoms over the course of several months.
“They may drink and pee more than usual and appear lethargic or weak,” Sperry says. “The most severe signs include collapse, seizures and even death. Pet owners may notice that their pet’s symptoms seem worse during periods of stress or excitement.”
Owners should look for the following common symptoms of dogs with Addison’s disease:
- Vomiting
- Diarrhea
- Weakness or lethargy
- Changes in drinking and urination habits
- Loss of appetite
- Weight loss
- Collapse
- Tremors or seizures
- Illness following stress
Is Addison’s Disease Covered by Pet Insurance?
Whether your pet insurance covers treatment for Addison’s disease will depend entirely on your individual coverage plan, and whether your dog was diagnosed before or after the coverage started.
There are some pet insurance companies that do cover pre-existing conditions with limitations.
What are the Stages of Addison’s Disease in Dogs?
Sperry notes that Addison’s disease is considered a chronic illness, but when it comes to designing a treatment plan, veterinarians will often divide the illness into two phases:
- Acute (Addisonian crisis): Requires emergency treatment
- Chronic: Requires lifelong management and care
“All pets with Addison’s need chronic treatment, but some never experience an Addisonian crisis,” Sperry notes.
There are also two forms of Addison’s disease:
- Typical: The dog is deficient in cortisol and aldosterone, which results in electrolyte abnormalities.
- Atypical: The dog is deficient in cortisol and electrolytes may be normal.
For typical Addison’s disease, the dog’s medical journey can look like the following:
- The owner will take their dog to the veterinarian a few times with vague gastrointestinal symptoms like appetite loss, vomiting or diarrhea.
- The veterinarian will conduct standard testing and/or provide typical treatment.
- If standard testing and typical treatment fail, the veterinarian will order advanced testing in order to identify the illness.
- Once diagnosed, the owner will have to manage their dog’s Addison’s disease with regular injections that are designed to replace the deficient hormones.
During the early stages of the disease, the dog is likely to exhibit symptoms including fatigue, nausea, weight loss and dizziness, Fleck says.
During the later stages of the disease, the dog is likely to exhibit signs and symptoms that include dark patches of wrinkling skin with dark hyperpigmented gums, abdominal pain and vomiting, diarrhea, muscle weakness with pain, joint pain, poor appetite, dehydration and hypotension, Fleck says.
How to Test for Addison’s Disease in Dogs
There are a number of tests used in the diagnosis and management of Addison’s disease, Sperry notes.
The initial testing usually includes standard health tests like a complete blood count test, serum biochemistry, electrolytes and stool/urine testing.
“Based on your dog’s clinical signs and the results of these tests, your vet may confirm a diagnosis of Addison’s by measuring cortisol in the blood or urine,” Sperry notes.
The most common test used to diagnose and confirm a diagnosis of Addison’s is called an adrenocorticotropic hormone (ACTH) stimulation test, Fleck says.
The ACTH stimulation test is performed over the course of two to three hours. It involves taking a small blood sample to measure baseline cortisol, giving an injection of a medication intended to stimulate cortisol release, and measuring cortisol levels again to see if the dog was able to respond.
Veterinarians may also turn to imaging such as abdominal ultrasound to visually evaluate the adrenal glands.
More recently, veterinarians at the University of California, Davis School of Veterinary Medicine have developed an algorithm that uses artificial intelligence (AI) to detect Addison’s disease in dogs. The algorithm has an accuracy rate greater than 99%.
Other than paying attention to signs and symptoms, there is no way for owners to determine at home that their dog has Addison’s disease, Sperry says.
“If you suspect Addison’s disease in your dog, the best thing you can do is make an appointment with your vet,” Sperry says.
“While you are waiting to see the vet, it is very important to minimize stress and excitement for your dog, and avoid strenuous activities,” she adds.
Treatment Costs for Dogs With Addison’s Disease
The total cost for treating Addison’s disease in dogs will vary depending on a variety of factors, including where you are located, the age and size of your dog and the severity of the disease.
“Addison’s disease is a very expensive disease to treat, manage and monitor,” Fleck says. Owners are likely to spend thousands of dollars when establishing initial diagnosis and treatment protocol, he notes.
“Expenses continue to mount into the thousands of dollars yearly for managing and monitoring,” Fleck adds.
Estimates of the average total costs to treat Addison’s disease in dogs include the following:
- Initial testing and diagnosis: $1,500 depending on the types of testing it takes for the diagnosis
- Regular testing, medication and monitoring: $50 to $200 a month depending on the medication required and your dog’s response
According to Canine Addison’s Resources & Education (CARE), a non-profit dedicated to providing education to improve the lives of dogs with Addison’s disease, dogs with atypical Addison’s disease require a daily glucocorticoid replacement, such as Prednisone. Dogs with typical Addison’s disease are treated with monthly shots of Percorten or Zycortal plus a daily glucocorticoid or with daily Florinef tablets.
Is Addison’s Disease Common in Senior Dogs?
Addison’s disease is most commonly found in young to middle-aged dogs.
The Merck Veterinary Manual notes that some breeds may be predisposed to Addison’s disease, including:
- Standard poodles
- West Highland white terriers
- Great Danes
- Bearded collies
- Portuguese water dogs
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