Understanding Addison’s Disease. How to Look After Your Dog’s Health

What is Addison’s disease in dogs?

Addison’s disease, also known as hypoadrenocorticism, is an endocrine disorder that occurs when the adrenal cortex fails to produce enough steroid hormones, notably cortisol and aldosterone. Cortisol plays a central role in regulating metabolism, the body’s response to stress and the maintenance of healthy blood glucose levels, while aldosterone governs the balance of water and electrolytes, including sodium and potassium levels. A shortage of these hormones can leave a dog with serious health problems such as weakness, vomiting and diarrhoea, as well as adrenal crises, which can be life-threatening. Addison’s disease usually develops gradually and may be brought on by a range of factors, among them autoimmune damage to the adrenal glands, which throws the dog’s hormonal balance out and in turn disrupts many vital functions.

Dog breeds predisposed to Addison’s disease

Addison’s disease can affect dogs of any breed, though some are noticeably more prone to it. It most commonly affects medium and large breeds, including:

• Retrievers (for example the Labrador Retriever and Golden Retriever)
• Boxers
• German Shepherds
• Bedlington Terrier
• Shar Pei

Several other breeds, including the Whippet, Poodle and Beagle, also carry an increased risk of developing Addison’s disease. There is evidence, too, that females are more susceptible than males. While breed predisposition does raise the risk, it is worth remembering that Addison’s disease can occur in crossbreeds as well.

Signs of Addison’s disease 

The signs of Addison’s disease in dogs vary and tend to appear gradually, which is why they are so often mistaken for other conditions. 

1. Weakness and apathy – dogs may seem tired, less active and reluctant to play.
2. Loss of appetite – dogs with Addison’s disease often show less interest in food, which can lead to weight loss.
3. Vomiting and diarrhoea – many affected dogs have bouts of vomiting and recurring diarrhoea, which can lead to dehydration.
4. Increased drinking and urination – shifts in electrolyte balance can cause excessive thirst (polydipsia) and increased urine production (polyuria).
5. Low blood pressure – a blunted response to stress can bring on dizziness and weakness.
6. Addisonian crisis – in the most severe cases a sudden adrenal crisis may occur, marked by profound weakness, muscle rigidity, trembling, a sharp drop in blood pressure and possible loss of consciousness. This is an emergency and calls for immediate veterinary attention.

Treating Addison’s disease in dogs

Treating Addison’s disease in dogs is a long-term undertaking focused on replacing the missing hormones and keeping their levels steady. The mainstay of therapy is hormone medication, most often corticosteroids such as prednisolone, which make up for the shortfall in cortisol. Doses are tailored to the individual dog, and medication may be needed daily or several times a week. Where aldosterone is lacking, mineralocorticoids such as fludrocortisone are used to help maintain electrolyte balance. Regular monitoring is equally important, covering electrolyte levels and the dog’s overall response to treatment. Owners should stay alert to both short- and long-term signs and offer support during stressful situations, which can trigger an adrenal crisis. Should a crisis occur, it can be life-threatening and requires immediate veterinary intervention, including intravenous fluids and medication.