🐶 Canine Hypoadrenocorticism in 2025: A Vet’s Guide to Addison’s Disease in Dogs 🩺

By Dr Duncan Houston, BVSc

🔍 What Is Canine Hypoadrenocorticism (Addison's Disease)?

Hypoadrenocorticism, more commonly known as Addison’s disease, is a rare but serious endocrine disorder in dogs 🧬. This condition results when the adrenal glands—tiny organs located near the kidneys—fail to produce enough essential hormones like cortisol and aldosterone.

Cortisol is crucial for metabolism and stress response, while aldosterone regulates water, sodium, and potassium balance. A deficiency in one or both of these hormones can lead to significant, sometimes life-threatening symptoms if left untreated. 🧪

📊 Types of Hypoadrenocorticism in Dogs

There are two main types of this disease, each with its own diagnostic and treatment challenges:

• Hyponatremic, Hyperkalemic Hypoadrenocorticism 🧂⚖️ – Also known as “typical Addison’s disease,” this form involves deficiencies in both cortisol and aldosterone, leading to electrolyte imbalances.
• Eunatremic, Eukalemic Hypoadrenocorticism 🧬 – Previously called “atypical Addison’s,” this type involves only a cortisol deficiency. Sodium and potassium levels remain within normal range.

⚠️ What Causes Addison’s Disease in Dogs?

The condition may result from:

• Autoimmune destruction of the adrenal glands (most common) 🧫
• Tumors or infections affecting the adrenal glands
• Damage to the pituitary gland, which controls adrenal hormone production
• Medications such as trilostane (Vetoryl) or mitotane, which may induce temporary or permanent adrenal suppression 💊
• Exogenous corticosteroid use (e.g., prednisone), which can suppress adrenal function temporarily

📉 Clinical Signs of Hypoadrenocorticism

Signs can be sudden and severe or slow and vague. The tricky part? These symptoms often mimic other conditions, earning Addison’s the nickname “the great pretender.” 🎭

🩺 Common Symptoms Include:

• Lethargy or general weakness 🛌
• Loss of appetite 🍽️
• Vomiting 🤮
• Diarrhea, sometimes bloody 💩
• Weight loss ⚖️
• Tremors or muscle stiffness 💪
• Depression or apathy 😞
• Dehydration and increased thirst/urination 💧

🚨 Hypoadrenal Crisis

In acute cases, dogs can collapse suddenly with vomiting and diarrhea. This emergency, known as an Addisonian Crisis, requires immediate veterinary care. Delay can be fatal. 🏥

🧬 Diagnosing Hypoadrenocorticism

Diagnosis often involves a combination of:

• Thorough physical exam
• Baseline cortisol test (to rule out the disease quickly)
• ACTH stimulation test – the gold standard for confirming Addison’s 💉
• Bloodwork (to check sodium, potassium, kidney function, and hydration status)
• Ultrasound or X-rays to rule out other conditions 📸

🐩 Breeds More Likely to Develop Addison’s Disease:

• Standard Poodles ✨
• Labradoodles & Goldendoodles 🧡
• Portuguese Water Dogs 🌊
• Nova Scotia Duck Tolling Retrievers 🦆
• Bearded Collies 🐕

💊 Treatment Options and Prognosis

Once diagnosed, dogs with Addison’s can lead long, healthy lives with proper treatment. The key is consistent hormone replacement and regular monitoring. 🩷

🧴 Cortisol Replacement

All affected dogs require a corticosteroid, usually one of the following:

• Prednisone
• Prednisolone
• Methylprednisolone
• Hydrocortisone

🧂 Aldosterone Replacement

There are two primary options:

• Florinef® – Given orally twice a day, includes mild corticosteroid activity
• Percorten® or Zycortal® – Long-acting monthly injections

Most vets prefer Percorten® or Zycortal® due to fewer side effects and better electrolyte control. However, response varies by dog. 🐶❤️

📅 Long-Term Management & Monitoring

Dogs with Addison’s require lifelong treatment. Missing doses or abrupt discontinuation can be life-threatening. ⚠️

👩‍⚕️ Veterinary Monitoring Includes:

• Biannual blood panels 🧪
• Electrolyte monitoring (sodium/potassium) ⚖️
• Urinalysis 💧
• Adjustment of medications during times of stress, surgery, travel, or illness ✈️🛁🏥

Some dogs on Florinef® may wean off added corticosteroids if stable. Those receiving Percorten® or Zycortal® will need corticosteroids for life, as these drugs replace only aldosterone. 📌

🏡 Lifestyle & Support for Dogs with Addison’s

With the right management, your dog can enjoy a full, active life. From daily walks to playtime in the park, they can thrive just like any other dog. 🌳🐾

📲 For personalized support, behavioral advice, or medication reminders, download the Ask A Vet App today! Our expert team is here to help guide your dog’s health journey—every step of the way. 🐕‍🦺📱

✅ Key Takeaways

• Addison’s disease is serious but manageable 🌟
• Symptoms may mimic many other illnesses 🤔
• Early diagnosis and treatment can save lives ⏱️
• Medications must be administered for life 💊
• Regular vet check-ups are essential 🧑‍⚕️
• Stress dosing with steroids during illness or excitement is critical ⚖️

🐾 Final Words from Dr Duncan Houston

If your dog is showing any of the symptoms discussed above—especially if they come and go, or worsen suddenly—speak with your vet. Canine hypoadrenocorticism may be rare, but it is very treatable. With proper diagnosis and care, your pup can live a long and happy life. 🐕❤️

And remember, if you ever need help interpreting test results, adjusting meds, or just want a second opinion, visit AskAVet.com or open the Ask A Vet App! Your dog deserves the very best care. 🌐🩺