Addison’s disease in dogs: early symptoms, testing and treatment

What is Addison's disease in dogs​?

Addison’s disease is caused by low levels of steroid hormones in a dog's body. These hormones — cortisol and aldosterone — are produced by the adrenal glands which sit next to the kidneys. They’re essential for your dog’s health, helping regulate stress and maintain water and electrolyte balance, among other important functions. Low levels of these hormones can cause a wide range of vague, fluctuating symptoms, with common signs including lethargy, not eating and vomiting. Addison’s disease is a fairly uncommon condition in dogs in the UK, but certain breeds are more affected than others, with Standard Poodles particularly at risk. 

If the condition is left untreated, dogs can experience sudden severe symptoms including weakness, trembling, vomiting, diarrhoea and collapse. This is a life-threatening condition known as an Addisonian crisis which requires emergency treatment. If you’re worried your dog might be affected then you should contact your vet right away. Addison’s can typically be managed with regular, life-long medication.

Key points

• Addison's disease occurs when a dog's adrenal glands don't produce enough of the steroid hormones cortisol and aldosterone
• Early symptoms are varied and can include lethargy, vomiting, and weight loss
• If untreated, Addison’s can develop into a life-threatening Addisonian Crisis, causing severe symptoms such as shaking and collapse.
• Diagnosis involves a combination of medical history review, tests like blood and urine analysis, and the ACTH stimulation test.
• Treatment for Addison's disease typically includes lifelong medication, such as monthly injections and daily tablets.
• Certain breeds, like Standard Poodles and Portuguese Water Dogs, are more prone to Addison's disease, and stress can worsen symptoms in affected dogs.

What causes Addison's disease in dogs​

Addison’s disease is usually caused by damage to the dog’s adrenal glands. This is most often due to an auto-immune condition — where the dog’s immune system accidentally attacks the glands. Other less common causes of damage include trauma and infection. Treatment for Cushing’s disease — a condition caused by an overproduction of cortisol — can also be to blame.

Dogs can get a secondary form of Addison’s disease as a result of damage to the pituitary gland, which is located at the base of the brain. It can also develop if long-term steroid treatment is stopped quickly.

What are the symptoms of Addison's disease in dogs

The early signs of Addison’s disease vary widely and are associated with many other illnesses. They can also be mild and only appear occasionally (known as ‘waxing-waning’ symptoms), making them difficult to recognise. Typical signs can include:

• Vomiting 
• Diarrhoea
• Not eating
• Not drinking
• Increased urination
• Weight loss

In the event of an Addisonian crisis, more severe symptoms can suddenly appear. Signs to look out for include:

• Vomiting
• Diarrhoea
• Shaking/muscle tremors
• Collapse/weakness

An Addisonian crisis is a medical emergency and can be fatal. Dogs treated quickly have a better chance of survival, so contact your vet right away if you have any concerns.

Testing and diagnosing Addison's disease in dogs

If you suspect your dog has Addison’s disease, contact your vet right away. They will make a diagnosis after reviewing your dog’s medical history and symptoms, and performing a series of tests. To begin with, they will probably want to know more about your dog’s symptoms, including when they appeared and how frequently you notice them, as well as any medications they might be on. Tests might include blood and urine analysis to check for signs, including anaemia and potassium and sodium imbalance. An ECG or ultrasound scan might be recommended if your vet thinks they are necessary.

To confirm your dog has Addison’s disease, your vet will perform an ACTH stimulation test. They will inject your dog with medication similar to the hormone ACTH and measure their cortisol levels by testing their blood before and after. ACTH is a hormone which stimulates the adrenal glands to release steroid hormones. In healthy dogs, injecting ACTH will cause a temporary spike in their blood levels of cortisol. However, in dogs with Addison’s disease, the adrenal glands will respond poorly to the injection, and very little cortisol will be produced. 

Addison’s disease is often diagnosed when a dog is brought to the vet during an Addisonian crisis as this is when their symptoms are most obvious. 

Treatment for Addison's disease in dogs

The type of treatment your vet will recommend depends on the severity of your dog’s condition, and the stage of the disease. Dogs suffering from an Addisonian crisis will need to stay at the vet to receive intensive treatment, including a drip to restore their fluid levels and electrolyte balance. Regular treatment typically includes a monthly injection and daily tablets to replace the hormones their body can’t produce. 

While Addison’s disease is incurable, dogs with the condition usually go on to live normal lives with regular, lifelong treatment. 

Living with a dog with Addison’s disease

Dogs with Addison’s disease have a fairly normal life expectancy with a good quality of life as long as the condition is managed with regular medication. If your dog has Addison’s you will need to make sure they always get their medication on time and take them to regular vet appointments. Keep an eye on their symptoms and get in touch with your vet if you notice any changes.

Stress can exacerbate the symptoms of Addison’s disease so try to avoid stressful situations where possible and speak to your vet ahead of particularly stressful times, such as bonfire night or New Year’s Eve. Medication levels may need to be adjusted in certain unavoidable situations such as a staying at a boarding kennel.  

What breeds are prone to Addison's disease?

While Addison’s can affect all dogs, there are some breeds that are more prone to the condition, including Standard Poodles, Portuguese Water Dogs, West Highland Terriers, Great Danes, and Bearded Collies. It is also slightly more common in young adult, female dogs.

Can stress cause Addison's disease in dogs​

Dogs with Addison’s disease can’t produce enough cortisol (the stress hormone), meaning their body doesn’t react well to stress. So, while stress doesn’t cause Addison’s disease, it is possible for stress to aggravate your dog’s symptoms worse and make them ill. While it’s impossible to completely avoid stress, you can minimise the risks by keeping them calm, minimising exposure to stressful situations and speaking to your vet if you need advice.

Need more info?

For more advice on Addison's disease, have a chat with your local vet.

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Sources

'Management of hypoadrenocorticism (Addison’s disease) in dogs' by Patty Lathan and Ann L Thompson. 'Hypoadrenocorticism in dogs under UK primary veterinary care: frequency, clinical approaches and risk factors' by I. Schofield et al.