Addison’s disease in dogs

Addison’s disease (also called hypoadrenocorticism) is a rare hormonal condition that occurs when a dog’s adrenal glands don’t produce enough steroid hormones, particularly cortisol and aldosterone. It can cause a wide range of symptoms, which may come and go, making it difficult to recognise in the early stages.

Although Addison’s disease can’t usually be cured, it can often be successfully managed with lifelong medication and regular veterinary monitoring. With the right treatment, many dogs with Addison’s disease continue to enjoy a good quality of life.

Because it’s a lifelong condition, treatment for Addison’s can become expensive. Insuring your dog early with a lifetime dog insurance policy, before any signs of illness, can help ensure they get the care they need if they become unwell.

What is Addison’s disease?

Addison’s disease is a condition where the adrenal glands don’t produce enough of the hormones the body needs to function properly. The adrenal glands are small glands located near the kidneys. They produce several important hormones, including:

• Cortisol, which helps the body respond to stress, regulate metabolism and support normal immune function.
• Aldosterone, which helps control the balance of sodium, potassium and water in the body.

When a dog doesn’t produce enough of these hormones, it can affect many different systems, including the digestive system, circulation and energy levels. Addison’s disease is sometimes described as the opposite of Cushing’s syndrome, where the body produces too much cortisol.

Causes of Addison’s disease

The most common cause of Addison’s disease in dogs is a condition where the immune system mistakenly attacks and damages the adrenal glands. This reduces their ability to produce the hormones the body needs.

Other, less common causes include:

• Damage to the adrenal glands caused by tumours, infection, inflammation or bleeding.
• Certain medications that interfere with adrenal function.
  Sudden withdrawal of long-term steroid medication.
• Problems affecting the pituitary gland, which controls signals sent to the adrenal glands.

In many cases, the exact reason the adrenal glands become damaged is unknown.

Breeds commonly affected by Addison's disease

Addison’s disease can affect any dog, but some breeds appear to have a higher risk of developing the condition.

Breeds that are diagnosed more frequently or considered at increased risk include:

• Standard Poodle
• Bearded Collie
• Portuguese Water Dog
• Great Dane
• Rottweiler
• West Highland White Terrier
• Soft Coated Wheaten Terrier

Female dogs are also diagnosed slightly more often than males.

However, Addison’s disease can occur in dogs of any breed, age or sex. Being a breed that’s considered at higher risk doesn’t mean a dog will definitely develop the condition.

Types of Addison’s disease

Addison’s disease is usually classified into three types depending on what’s causing the hormone deficiency.

Primary Addison’s disease

Primary Addison’s disease is the most common form. It occurs when the adrenal glands themselves become damaged and can no longer produce enough cortisol and aldosterone.

In most cases, this happens because the body’s immune system mistakenly attacks and damages the adrenal tissue.

Secondary Addison’s disease

Secondary Addison’s disease is a less common form that happens when the pituitary gland in the brain doesn’t send the right signals to the adrenal glands. Without these signals, the adrenal glands don’t produce enough cortisol.

Unlike primary Addison’s disease, the adrenal glands themselves are usually not damaged, and aldosterone levels are often unaffected.

Iatrogenic Addison’s disease

Iatrogenic Addison’s disease can occur after long-term steroid use or when medication used to treat Cushing’s syndrome reduces adrenal hormone production too much.

Vets usually manage this type by carefully adjusting medication.

Symptoms of Addison’s disease

The signs of Addison’s disease can vary considerably and often develop gradually. Some dogs may appear unwell for a short period before seeming to recover.

Common symptoms include:

• Lethargy or reduced energy
• Loss of appetite
• Weight loss
• Vomiting
• Diarrhoea
• Increased thirst
• Increased urination
• Weakness
• Shaking or trembling
• Abdominal pain
• Low mood or appearing unusually quiet

Blood tests may show changes such as low sodium levels and high potassium levels, which can be a clue that Addison’s disease may be present.

Signs of an Addisonian crisis

In some dogs, the first noticeable sign is an Addisonian crisis. This is a life-threatening emergency caused by a severe lack of adrenal hormones.

Signs of an Addisonian crisis can include:

• Collapse
• Severe weakness
• Repeated vomiting or diarrhoea
• Dehydration
• Very low blood pressure
  Shock

Without urgent veterinary treatment, an Addisonian crisis can be fatal.

What to do if your dog shows signs of Addison’s disease

If your dog shows ongoing symptoms such as unexplained tiredness, reduced appetite, vomiting, diarrhoea, weight loss or increased drinking, arrange an appointment with your vet.

Addison’s disease can be difficult to diagnose because its symptoms can look similar to many other conditions. Your vet may recommend blood tests, urine tests and other investigations to rule out other causes.

If Addison’s disease is suspected, an ACTH stimulation test is commonly used to confirm the diagnosis. This test checks how the adrenal glands respond to stimulation and whether they’re producing enough cortisol.

Seek emergency veterinary advice immediately if your dog collapses, becomes severely weak or appears very unwell, as this may indicate an Addisonian crisis.

What age could you expect Addison’s disease in your dog?

Addison’s disease can occur at any age, but it’s most commonly diagnosed in young to middle-aged dogs. Many cases are identified between around 2 and 7 years of age, although older dogs can also develop the condition.

Because the symptoms can be vague and intermittent, diagnosis may sometimes be delayed.

How to manage Addison’s disease

Addison’s disease usually requires lifelong management, but most dogs respond well to treatment. Management typically involves replacing the hormones that the adrenal glands are no longer producing. This may include:

• Mineralocorticoid replacement, to help control sodium and potassium balance.
• Glucocorticoid replacement, to replace cortisol and help the body respond to stress.

Your dog will usually need regular veterinary check-ups and blood tests to monitor hormone levels and adjust medication doses.

At home, it’s important to give medication exactly as prescribed and attend regular monitoring appointments. You should also watch for changes in appetite, thirst, energy levels or general behaviour.

Speak to your vet if your dog becomes unwell, as medication may need adjusting during periods of stress or illness

With appropriate treatment, many dogs with Addison’s disease live normal, active lives.

Does pet insurance cover Addison’s disease?

Pet insurance may cover Addison’s disease if your dog develops the condition after your policy begins and it’s not considered a pre-existing condition.

Depending on your policy, insurance may help with eligible costs such as veterinary consultations, diagnostic tests, emergency treatment, and prescription medication.

As Addison’s disease is usually a lifelong condition, lifetime pet insurance can be particularly valuable.

Addison’s disease treatment options

Treatment depends on whether a dog is experiencing an Addisonian crisis or has been diagnosed with a long-term condition.

Emergency treatment

Dogs experiencing an Addisonian crisis need urgent veterinary care. 
Treatment may include intravenous fluids to correct dehydration and electrolyte imbalances, steroid medication to replace missing hormones, and other medication to help stabilise blood pressure and circulation.

Your vet will also closely monitor your dog’s heart rate, electrolyte levels and overall condition. Once your dog is stable, your vet can create a long-term treatment plan to help manage the condition.

Long-term treatment

Dogs with Addison’s disease usually need lifelong hormone replacement therapy.

Treatment may include mineralocorticoid replacement injections or tablets to help control sodium and potassium levels, alongside daily steroid medication to replace cortisol.

Your vet will regularly check your dog’s hormone levels and adjust medication doses when needed to keep the condition under control.

When to speak to a vet

Contact your vet if you notice signs such as:

You should seek urgent veterinary advice if your dog collapses, becomes extremely weak, can’t stand, or develops severe vomiting or diarrhoea.

Although Addison’s disease can be serious, early diagnosis and appropriate treatment can make a significant difference. With lifelong management and regular veterinary care, many affected dogs can enjoy a good quality of life.