Addison's disease in dogs - "the great pretender"

Addison's disease in dogs - "the great pretender"

When it comes to canine health, some conditions are easy to spot — a limping dog, an itchy rash, or a bout of vomiting that clearly has a cause. But Addison’s disease is different. Quiet, subtle, and often mimicking other illnesses, Addison’s is known in veterinary circles as “the great pretender.”  This can, at times delay the diagnosis.

Yet despite its dramatic name, Addison’s disease is very treatable, and dogs can go on to live long, happy lives once diagnosed.

What Is Addison’s Disease?

Addison’s disease is named after Thomas Addison, a British physician who first described the condition in 1855.

Addison’s disease — or hypoadrenocorticism — occurs when the adrenal glands fail to produce enough of two essential hormones:

  • Cortisol, the body’s stress-coping hormone
  • Aldosterone, which regulates electrolytes, hydration, and blood pressure

Without these hormones, the body cannot maintain normal balance, leading to vague symptoms that often come and go. This makes Addison’s notoriously easy to miss without specific testing.

 

Common Signs and Symptoms

Early symptoms can be subtle and intermittent. Owners may notice their dog is “just not themselves” for days or weeks at a time. Signs include:

  • Lethargy or unusual tiredness
  • Vomiting or diarrhea
  • Loss of appetite
  • Weight loss
  • Shaking or trembling
  • Increased drinking or urination
  • Dehydration
  • Muscle weakness
  • A slow heart rate — a classic red flag

In severe cases, dogs may collapse suddenly. This is known as an Addisonian crisis, a life-threatening emergency caused by dangerously low cortisol and electrolyte imbalance.

 

 

 

Causes of Addison’s disease

In most dogs, Addison’s occurs as an autoimmune condition, when the immune system mistakenly destroys the adrenal gland tissue.

Less common causes include:

  • Certain medications, especially those used to treat Cushing’s disease (hyperadrenocorticism – so the polar opposite)
  • Tumours
  • Long-term steroid use followed by sudden withdrawal
  • Severe infections affecting the adrenal glands

Any dog can develop Addison’s (I have seen it cross breeds as well), though it’s seen more often in the following breeds:

  • Standard Poodles
  • Bearded Collies
  • West Highland White Terriers
  • Portuguese Water Dogs
  • Rottweilers
  • Great Danes

Young to middle-aged female dogs tend to be overrepresented. Again, any age and gender can be affected.

 

Addison’s diagnosis

Diagnosis starts with history and basic blood work. Often ruling out other conditions begins the process.  Many Addisonian dogs show:

  • Low sodium
  • High potassium
  • Low chloride
  • Sometimes low blood sugar

The gold standard test is the ACTH stimulation test, which checks how the adrenal glands respond to stimulation. In Addison’s disease, cortisol levels barely rise, confirming the diagnosis.

 

 

Treatment: From Crisis to Long-Term Care

 *During an Addisonian Crisis

A crisis is an emergency requiring immediate veterinary care. Treatment includes:

  • IV fluids to correct dehydration
  • Medications to balance electrolytes
  • Injectable steroids
  • Careful monitoring

Dogs often bounce back quickly once these imbalances are corrected.

 

*Long-Term Management

Addison’s disease is lifelong, but very manageable. Treatment replaces the hormones the body can’t produce:

  • Mineralocorticoids
    • DOCP (injection every 3–4 weeks)
    • or Fludrocortisone (daily tablets)
  • Glucocorticoid (Prednisone)
    • Daily small dose
    • Increased temporarily during stress, travel, vet visits, or illness

Most owners quickly become confident in managing the condition at home.

 

Living With Addison’s Disease

The good news? Dogs with Addison’s disease can live completely normal, joyful lives once stabilized on treatment. Many go years without complications.

The key to success is:

  • Consistent medication
  • Routine monitoring
  • Stress-dose steroids when advised
  • Watching for early signs of imbalance

With proper care, most dogs thrive — playing, hiking, and enjoying life just like any other dog.

 

 

Alternative management options

Herbal supplements can be very effective in managing symptoms.

·        Liquorice specifically has shown to be useful in Addison's, but it must be closely followed as it may cause complications in certain instances. Best to involve your vet when using Liquorice.

·         Other herbs that could be useful are Ashwaganda and Ginseng

·         Lifewave Aeon and SP6 could be beneficial in stable patients.

 

 

Final Thoughts

Addison’s disease may be a master of disguise, but awareness is powerful. If your dog shows vague, recurring episodes of vomiting, weakness, or collapse — especially combined with abnormal electrolytes — Addison’s should always be on the list of possibilities.

Early diagnosis and lifelong treatment turn what could be a dangerous condition into a manageable and stable part of your dog’s health journey.

Back to blog