Addison’s Disease in Dogs

Even though it’s uncommon, it’s a serious condition that can be life-threatening if not treated properly.

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What Causes Addison’s Disease?

Addison’s disease occurs when a dog’s immune system mistakenly attacks the adrenal glands’ outer layers. These glands are responsible for producing essential hormones that help maintain the right balance of sodium, potassium, and water in the body. When this balance is off, muscles—including the heart—can’t work properly.

Additionally, another part of the adrenal glands produces cortisol, a hormone that plays a big role in processing proteins, carbs, and sugars.

Sometimes, dogs being treated for Cushing’s disease (a condition where the body produces too many of these hormones) can develop Addison’s disease if their treatment ends up damaging the outer layers of their adrenal glands.

Symptoms to Watch For

Addison’s disease is often called “the great imitator” because its symptoms can mimic many other health problems, like kidney issues or digestive disorders. Unfortunately, about 80–90% of the adrenal glands need to be damaged before the symptoms become obvious enough to diagnose.

Here are the most common signs, which can range from mild to severe:

• Digestive Issues: Vomiting, diarrhea, poor appetite, and weight loss. Symptoms often come and go, so it’s easy to mistake them for something minor.

• Lethargy & Weakness: Imbalanced electrolytes and dehydration can leave your dog feeling tired or weak.

• Increased Thirst & Urination: When the sodium-potassium balance is off, it affects how well the kidneys manage water.

• Addisonian Crisis (Emergency Situation): In severe cases, dogs can suddenly become very sick. Symptoms include extreme dehydration, severe weakness, and even heart failure. Many dogs that experience this crisis have a history of having a “sensitive stomach” but weren’t previously diagnosed with Addison’s disease.

How Is Addison’s Disease Diagnosed?

A simple blood test can sometimes reveal high potassium and low sodium levels, but it’s not always that straightforward—sometimes, blood results come back looking perfectly normal.

If your vet suspects Addison’s disease, they’ll likely recommend an ACTH stimulation test. This test checks how well your dog’s adrenal glands respond to a hormone called ACTH, which helps confirm the diagnosis.

Treating Addison’s Disease

If your dog is in crisis, they’ll need immediate medical care, including hospitalization, IV fluids, and cortisone medication to stabilize their condition. This treatment often starts before final test results are even available because of how severe an Addisonian crisis can be.

Once diagnosed, dogs with Addison’s disease require lifelong treatment, which may include:

• Florinef: A daily oral medication that works well for some dogs.

• Percortin: An injectable medication given every 21–28 days. Some dogs may feel weak or tired if they miss their usual dose by even a day or two.

• Prednisone: Some dogs will also need regular doses of this medication to stay healthy.

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Regular check-ups and monitoring are essential, but the good news is that with proper treatment, dogs with Addison’s disease can go on to live happy, normal lives.