Dog Addison's Disease: A Hidden but Manageable Condition

Hypoadrenocorticism (Addison's disease) is a life-threatening but highly manageable hormonal disorder in dogs that is frequently misdiagnosed due to its vague, episodic symptoms. Early diagnosis enables excellent long-term outcomes.

Key Facts

Addison's disease results from insufficient production of cortisol and aldosterone by the adrenal glands
It affects all dog breeds but is overrepresented in Standard Poodles, Portuguese Water Dogs, Bearded Collies, and Great Danes
The classic presentation includes episodic weakness, lethargy, vomiting, and diarrhea — often called "the great pretender"
Addisonian crisis is a life-threatening emergency with severe weakness, shock, and cardiovascular collapse
Diagnosis requires an ACTH stimulation test — basal cortisol alone is insufficient
Approximately 30% of dogs are diagnosed only after presenting in Addisonian crisis
Treatment involves lifelong mineralocorticoid replacement (fludrocortisone or DOCP injection) plus glucocorticoid supplementation during stress
With proper treatment, most dogs have a normal lifespan and excellent quality of life

Welfare Considerations

Addison's disease causes episodic suffering that is particularly distressing because it is unpredictable and often severe. Dogs in Addisonian crisis are profoundly weak, nauseated, and can die rapidly without aggressive IV fluid and steroid therapy. The nonspecific nature of signs — waxing and waning over months to years — means many dogs suffer through repeated episodes before diagnosis. Once diagnosed and stabilized, the welfare picture improves dramatically. DOCP injections every 25-28 days provide consistent mineralocorticoid levels, and daily prednisolone provides cortisol. Owners must understand the need for stress-dose steroids during illness, injury, or surgery. Dogs on stable treatment live full, comfortable lives with regular monitoring.

What You Can Do

Investigate Addison's disease in any young to middle-aged dog with episodic GI signs and lethargy
Request an ACTH stimulation test if Addison's is suspected — do not rely on basal cortisol alone
If your dog has Addison's, always carry an emergency hydrocortisone injection for crisis situations
Inform all vets and groomers that your dog has Addison's and may need stress-dose steroids
Administer medications consistently — skipping doses risks life-threatening crisis
Monitor for signs of inadequate control: weakness, vomiting, or weight loss between checks