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Addison’s Disease (Hypoadrenocorticism) in Dogs: Symptoms, Causes, Treatment, and Prevention

Addison’s disease, medically known as hypoadrenocorticism, is an endocrine disease in which the adrenal glands produce too little cortisol and aldosterone, the hormones that regulate stress response and the body’s salt and water balance.

Addison’s disease is sometimes called “the great pretender” because its early symptoms are vague and can mimic many other illnesses, which makes it a disease veterinarians stay alert for even when the presentation isn’t obvious. This guide covers what causes Addison’s disease, its symptoms, how it’s diagnosed, how it’s treated, whether it can be prevented, and when to see a veterinarian.

This guide covers what Addison’s disease is, what causes it in dogs, its symptoms, how it’s diagnosed, how it’s treated, whether it can be prevented, when to see a vet, and what else people ask.

What Is Addison’s Disease in Dogs?

Addison’s disease, or hypoadrenocorticism, is a chronic endocrine disease in which the adrenal glands fail to produce enough cortisol and aldosterone, hormones essential for managing stress response, blood pressure, and the body’s sodium and potassium balance. The deficiency develops gradually in most dogs, and because cortisol and aldosterone affect so many body systems, the resulting symptoms are often subtle and easy to mistake for other, less serious conditions until the disease progresses. Left untreated, Addison’s disease can progress to a sudden, life-threatening crisis.

What Causes Addison’s Disease in Dogs?

The most common cause of Addison’s disease in dogs is autoimmune destruction of the adrenal cortex, where the immune system mistakenly attacks and gradually destroys the tissue responsible for producing cortisol and aldosterone. A less common form, called secondary Addison’s disease, results from a problem with the pituitary gland failing to signal the adrenal glands properly rather than damage to the adrenal glands themselves. Addison’s disease can also develop after abruptly stopping long-term steroid medication, since the adrenal glands can become suppressed and slow to resume normal hormone production. The disease most often affects young to middle-aged female dogs, and certain breeds, including the Standard Poodle, Portuguese Water Dog, Bearded Collie, Nova Scotia Duck Tolling Retriever, and West Highland White Terrier, carry a documented predisposition.

What Are the Symptoms of Addison’s Disease in Dogs?

Addison’s disease often produces vague, waxing-and-waning symptoms including lethargy, vomiting, diarrhea, reduced appetite, and weight loss, which can look like a mild stomach upset that comes and goes over weeks or months. Many owners first notice their dog seeming “off” periodically without a clear pattern, since symptoms can improve temporarily before returning. The most dangerous presentation is an Addisonian crisis, a sudden, severe episode involving collapse, extreme weakness, and shock caused by dangerous electrolyte imbalances, which is a genuine medical emergency requiring immediate veterinary care.

How Is Addison’s Disease in Dogs Diagnosed?

A veterinarian typically starts an Addison’s disease workup after routine bloodwork reveals characteristic electrolyte abnormalities, particularly an elevated potassium level paired with a low sodium level. An ACTH stimulation test confirms the diagnosis by measuring how well the adrenal glands respond to a hormonal trigger that should normally stimulate cortisol production, and dogs with Addison’s disease show a minimal or absent response. Because the disease’s everyday symptoms are so nonspecific, many dogs undergo testing for several other conditions before Addison’s disease is identified as the actual cause.

How Is Addison’s Disease in Dogs Treated?

Addison’s disease is treated with lifelong hormone replacement therapy, most commonly either a monthly injectable medication or a daily oral medication that replaces the missing aldosterone, paired with a low daily dose of oral prednisone to replace cortisol. A veterinarian monitors a treated dog’s electrolyte levels periodically and adjusts the dose as needed, since requirements can shift over time and especially during periods of physical or emotional stress. A dog experiencing an Addisonian crisis needs emergency hospitalization for intravenous fluids and immediate hormone treatment to stabilize dangerous electrolyte levels.

Can Addison’s Disease in Dogs Be Prevented?

Addison’s disease caused by autoimmune destruction of the adrenal glands generally can’t be prevented, since the underlying immune process isn’t something an owner can control. The exception is Addison’s disease triggered by abrupt steroid withdrawal, which can often be avoided by tapering a long-term steroid medication gradually under veterinary guidance rather than stopping it suddenly. Because early symptoms are so easy to miss, routine veterinary bloodwork that catches electrolyte abnormalities early gives a dog the best chance at diagnosis before a crisis develops.

When Should You See a Vet for Addison’s Disease in Dogs?

See a veterinarian if a dog shows recurring, unexplained episodes of lethargy, vomiting, diarrhea, or reduced appetite that come and go without an obvious cause, since this pattern is a classic presentation of Addison’s disease. Seek emergency veterinary care immediately if a dog collapses, becomes severely weak, or shows signs of shock, since this can indicate an Addisonian crisis requiring urgent treatment. A dog already diagnosed with Addison’s disease should also see a veterinarian promptly before any anticipated stressful event, such as boarding or travel, since stress can increase hormone requirements.

What Else Do People Ask About Addison’s Disease in Dogs?

The questions below cover whether Addison’s disease is curable, which dogs are most at risk, how serious an Addisonian crisis is, and whether Addison’s disease shortens a dog’s lifespan.

Is Addison’s disease in dogs curable?

No, Addison’s disease in dogs is not curable, since it results from permanent damage to or dysfunction of the adrenal glands’ hormone-producing tissue. It is, however, very manageable with lifelong hormone replacement therapy, which allows most dogs to live a normal life once properly diagnosed and treated.

Which dogs are most at risk for Addison’s disease?

Young to middle-aged female dogs face the highest documented risk for Addison’s disease, and several breeds, including the Standard Poodle, Portuguese Water Dog, Bearded Collie, Nova Scotia Duck Tolling Retriever, and West Highland White Terrier, show an elevated genetic predisposition. Dogs coming off long-term steroid medication also face a risk of developing the condition if the medication is stopped too abruptly.

How serious is an Addisonian crisis?

An Addisonian crisis is a genuine medical emergency and can be fatal without immediate treatment, since the severe electrolyte imbalance it causes can disrupt normal heart rhythm and lead to shock. Dogs that receive prompt emergency treatment for a crisis generally recover well and can return to stable, long-term management afterward.

Does Addison’s disease shorten a dog’s lifespan?

Well-managed Addison’s disease generally doesn’t shorten a dog’s lifespan, since lifelong hormone replacement therapy effectively replaces what the body can no longer produce on its own. The real risk to lifespan comes from an undiagnosed or poorly managed case progressing to a crisis, which is why consistent veterinary follow-up matters for dogs living with this condition.

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