Dog Addison's Symptoms: Signs, Causes, and What to Do Next

When a dog has Addison's disease, a serious hormonal disorder caused by the adrenal glands not producing enough cortisol and aldosterone. Also known as canine adrenal insufficiency, it’s often mistaken for a stomach bug or general weakness—until it becomes life-threatening. Many pet owners don’t realize their dog is suffering until symptoms get severe. That’s because the signs are subtle at first and come and go, making them easy to ignore.

Common dog Addison's symptoms include vomiting, diarrhea, loss of appetite, lethargy, and shaking. Some dogs drink more water than usual or urinate more frequently. Others suddenly collapse after exercise or stress. These aren’t random quirks—they’re red flags that the body’s stress response system has failed. Without enough cortisol, the dog can’t handle even normal daily stressors. Without aldosterone, electrolytes like sodium and potassium go out of balance, which can trigger heart rhythm problems. This isn’t just fatigue—it’s a metabolic crisis.

What causes it? In most cases, the immune system attacks the adrenal glands by accident. Less often, it’s triggered by long-term steroid use, tumors, or trauma. Certain breeds like Standard Poodles, Portuguese Water Dogs, and Bearded Collies are more prone, but any dog can develop it. Age matters too—it usually shows up in middle-aged dogs, but younger ones aren’t immune. The key is catching it before the dog hits an Addisonian crisis, where they go into shock and need emergency IV fluids and steroids. That’s why knowing the early signs is so important.

If your dog has had unexplained vomiting or low energy for weeks, don’t wait. A simple blood test can check electrolyte levels and cortisol response. Early diagnosis means treatment with daily medication—often just a pill and a monthly injection. Many dogs live normal, active lives once stabilized. The alternative? Waiting until they collapse. That’s when costs spike, recovery takes longer, and the risk of death rises.

Below, you’ll find real-world guides from vets and pet owners who’ve walked this path. You’ll see how symptoms were spotted, what tests actually revealed, and how treatment plans changed over time. No fluff. Just what works.