If your dog has been diagnosed with Addison’s disease, or you’re worried they may have it, you probably have a lot of questions. Since it’s such a rare condition, it can be hard to find answers.  Even if your dog is healthy, it’s helpful to know a bit about Addison’s so you can watch for warning signs and reach out to your veterinarian quickly. 

Let’s discuss the causes, indications, and treatment of Addison’s disease in dogs. 

What Is Addison’s Disease in Dogs?

Addison’s disease, also known as hypoadrenocorticism, occurs when the adrenal glands (located near the kidneys) fail to produce essential hormones, such as cortisol and aldosterone. 

These hormones are essential for regulating life-sustaining functions such as metabolism and blood pressure, managing stress, suppressing inflammation, and balancing levels of potassium and sodium. Low levels of these hormones can cause illness and can even be fatal.

While dogs of any age can have Addison’s disease, the average age of diagnosis is 4 years old.¹ Female dogs appear to be affected more than male dogs. In fact, reports show that between 60% and 70% of cases are female.¹

Is Addison’s Disease in Dogs Hereditary? 

There does appear to be a hereditary component to Addison’s, especially in certain breeds, but genes aren’t the sole cause. The exact way the disease is inherited isn’t fully understood, and other factors play a role in whether a dog develops the condition.

Breeds that are predisposed to the disease include:^2,3

• Bearded Collie
• Great Dane
• Labrador Retriever
• Leonberger
• Nova Scotia Duck Trolling Retriever
• Portuguese Water Dog
• Rottweiler
• Standard Poodle
• West Highland White Terrier
• Wheaton Terrier

What Causes Addison’s Disease in Dogs?

In most cases, Addison’s is caused by the immune system attacking the adrenal cortex, limiting the production of necessary hormones. There really isn’t anything you can do to prevent this type of autoimmune response before your dog is diagnosed. 

Damaged adrenal gland tissue due to cancer, infection, or trauma has been known to cause Addison’s, though it’s rare. This is another case where prevention isn’t possible, other than avoiding the triggering infection or trauma, when possible. 

Use of certain medications can lead to Addison’s, those treating Cushing’s disease or rapidly stopping steroids after long term use. In this scenario, you do have some means of prevention by working closely with your veterinarian. 

Medications May Cause Addison’s Disease 

Addison’s disease can be a result of medication used to treat Cushing’s disease in dogs. If the medications used to treat this condition cause a deficiency of cortisol and aldosterone, this would cause Addison’s.

Addison’s disease can also occur when long-term use of steroids is suddenly stopped. Steroids cause the adrenal glands to shrink, resulting in hormone levels too low to meet the body’s needs. This is referred to as iatrogenic hypoadrenocorticism and is usually temporary. 

Secondary Addison’s Disease in Dogs 

Secondary Addison’s disease is a rare form that occurs when there’s an issue with the pituitary gland instead of the adrenal glands.

The pituitary gland, located in the brain, produces adrenocorticotropic hormone (ACTH) and stimulates the adrenal glands to produce cortisol.

If the pituitary gland is defective or a tumor grows near it, the gland won’t produce enough ACTH. In turn, the adrenal glands won’t produce enough cortisol, leading to secondary Addison’s.

Signs of Addison’s Disease in Dogs 

The signs of Addison’s disease mimic those of other more common medical conditions, which is why the disease is known as “the great pretender.”² Signs also often develop slowly and come and go. This combination can make the diagnosis of Addison’s challenging.

Signs of Addison’s disease in dogs include:

• Dehydration
• Diarrhea, which may contain blood
• Increased thirst and urination
• Intermittent shaking episodes
• Lethargy
• Loss of appetite
• Vomiting
• Weakness
• Weight loss

Does Addison’s Disease in Dogs Come on Suddenly?

While signs of Addison’s often start slowly, some dogs can have a sudden onset of serious signs, leading to an emergency condition known as Addisonian crisis. In this case, immediate veterinary care is vital. 

During an Addisonian crisis, dogs may show the following signs:

• Severe diarrhea
• Severe vomiting
• Sudden weakness
• Collapse

How to Test for Addison’s Disease in Dogs

If you think your dog may be suffering from Addison’s disease or is experiencing an Addisonian crisis, it’s crucial to see your veterinarian as soon as possible. They will perform initial screening tests, like a basic blood panel, urinalysis, X-rays, and an abdominal ultrasound.

They may also recommend an ACTH stimulation test to measure your dog’s cortisol levels before and one to two hours after an injection of a synthetic form of ACTH. If a dog has Addison’s disease, the pre-injection cortisol level will be low and will have little to no increase one to two hours following the injection. 

Treatment for Addison’s Disease in Dogs

Addison’s disease can be successfully treated in most cases, but usually requires lifelong management. 

Treatment involves supplementation with cortisol and aldosterone, either orally or via injection. Your veterinarian will determine which medications and routes are most suitable for your dog’s condition.

Treatment for an Addisonian crisis involves hospitalization for continuous monitoring, intravenous fluids, and medications. 

With proper diagnosis and treatment, the prognosis for many dogs is good to excellent.³ Even dogs who have an Addisonian crisis can recover well.³

For dogs who don’t receive treatment, this disease can be fatal. That’s why it’s so important to keep up with your dog’s regular veterinary checkups and let your veterinarian know if you see any of the signs of Addison’s disease.