What is Addison’s Disease in dogs?

Addison’s disease (or hypoadrenocorticism) occurs when the adrenal glands do not produce enough steroid hormones most commonly due to being attacked by the dog’s immune system. The adrenal hormones are very important for controlling salt and water balance, as well as for helping to deal with stress – they are essential for life. A lack of these hormones causes serious problems within the body that can be life-threatening.

Addison’s disease is most common in young to middle-aged dogs, and female dogs are more often affected. Certain breeds appear to be predisposed, including standard poodles, bearded collies, Portuguese water dogs, Leonbergers, Nova Scotia duck tolling retrievers and Labradors.

What are the symptoms of Addison’s Disease in dogs?

The symptoms of Addison’s disease usually develop slowly and can be vague, waxing and waning, and it can therefore be difficult to spot. Symptoms typically include the following:

• Lethargy and not being “quite right”
• Diarrhoea and vomiting
• Weight loss
• Loss of appetite
• Drinking and urinating more than usual

However, in some cases Addison’s develops much more quickly and causes sudden and life-threatening illness – an Addisonian crisis:

• Vomiting and diarrhoea
• Sudden collapse and coma
• Death if left untreated

How is Addison’s Disease in dogs diagnosed?

Given that the symptoms of Addison’s can often be vague it can be tricky to diagnose. The vet will use a combination of the clinical history, urine and blood tests, particularly looking at electrolyte imbalances. A particular blood test called the ACTH stimulation test is often used to confirm the diagnosis of Addison’s.

How is Addison’s Disease in dogs treated?

Treatment will depend on how your dog has presented. If they are suffering from an Addisonian crisis then they will need emergency treatment that will include intravenous fluid therapy, injectable steroids and other treatment to stabilise their condition. Once stable, maintenance therapy can begin to control their Addison’s.

Thankfully, Addison’s is relatively easy to treat, by replacing the dog’s own adrenal hormones with synthetic equivalents. This is usually done via a combination of a monthly long-acting injection and daily tablets where needed. It is important to avoid stress where possible, as your dog is less able to cope with this due to their lack of adrenal hormones. Where a stressful event is unavoidable e.g. fireworks, then the vet may recommend a higher dose of the tablet medication during this period, but never adjust the medication without speaking to your vet first. Treatment is life-long and the dog must be monitored with treatment adjustments made as necessary.

What is the prognosis of Addison’s Disease in dogs?

While an Addisonian crisis can certainly be life-threatening, once your dog has been stabilised and started on a maintenance treatment regime the outlook for most dogs with Addison’s is very good. If their condition is well controlled then they are likely to live a relatively normal life.