Cushing’s disease in dogs: causes, symptoms and management

What is Cushing’s disease in dogs?

When a dog has Cushing’s disease (also known as hyperadrenocorticism), their body makes too much of the hormone cortisol. Increased hunger and thirst are common early signs and without treatment Cushing’s can lead to other serious illnesses like diabetes and heart failure.

It’s most common in middle-aged and older dogs and the signs can be difficult to spot as they can be mistaken for the natural signs of ageing. 

Key points

• Cushing’s disease is caused by the production of too much cortisol
• Early symptoms include increased drinking, urinating, eating, panting, and changes in skin and energy levels
• If left untreated, it can lead to life-threatening conditions like diabetes, heart failure, and kidney problems
• Cushing’s can't be cured, but with medication many dogs can live active lives 
• What does Cushing’s disease do to dogs? 
• Cortisol is a steroid hormone. In normal amounts, cortisol is vital for your dog’s health. It helps them deal with stress, control their weight, fight infections, and regulate blood sugar levels. Too much cortisol can cause symptoms including increased thirst, hunger and urination, and skin problems. 
• If it’s not treated, Cushing's leaves your dog more vulnerable to other life-threatening conditions including congestive heart failure, diabetes, and liver or kidney failure. 
• It’s also a problem when dogs don’t produce enough cortisol, which is a condition known as Addison’s disease (hypoadrenocorticism).

Causes of Cushing’s disease in dogs

Cushing's is caused by a tumour, either in the pituitary gland which sits at the base of the brain, or in the adrenal glands which are near the kidneys. The pituitary gland tells the adrenal gland when to produce cortisol. If a tumour is growing on either of these glands then excess cortisol can be produced.

Pituitary dependent Cushing’s disease is the most common type, affecting 80-90% of diagnosed dogs, while adrenal dependent Cushing’s disease affects between 10-20% of diagnosed dogs.

A third type, iatrogenic Cushing's disease, can develop in dogs given steroid medication for other conditions. If you think your dog might be affected, speak to your vet about your concerns.

Does Cushing’s mean my dog has cancer?

The tumours that cause Cushing’s disease can either be benign (non-cancerous), or malignant (cancerous), and most cases of Cushing’s are caused by a non-cancerous tumour. So, if your dog has Cushing’s disease it doesn’t necessarily mean they have cancer. 

Symptoms of Cushing’s disease

Symptoms of Cushing’s disease can often be attributed to your dog simply getting older. They can also be quite subtle at first, making them even more difficult to spot. The first signs you might notice include your dog drinking more water and wanting to go to the toilet more frequently, as well as an increase in eating and panting. 
As the disease progresses they might seem less energetic and you might see changes on their skin and body. All types of Cushing’s disease produce the same symptoms but the treatment for each type will be different. 
Signs of Cushing’s to look out for include:

• Increased thirst
• Increased appetite 
• Increased urination 
• Lethargy and tiredness
• Increased panting (even when resting and not hot)
• Hair loss
• Bulging belly (pot belly)
• Skin lumps or infections

A bulging belly could also be a sign of bloat, which is life-threatening and needs immediate treatment. If you’re worried at all then get in touch with your vet right away for advice.

When to see a vet

It’s a good idea to book an appointment with your vet when you notice any of the symptoms of Cushing’s. The longer the disease is left untreated the more severe your dog’s symptoms can become and the more susceptible they are to other life-threatening conditions. If you’re worried that the symptoms need to be treated urgently, then call your vet right away.

Diagnosing Cushing’s disease in dogs 

There is no single test that can confirm if your dog has Cushing’s disease, so your vet will typically use a combination of tests to make a diagnosis. They’ll start by examining your dog and finding out more about their symptoms to rule out any other conditions. Blood and urine samples, scans, and tests to monitor cortisol levels might be used to help confirm that Cushing’s is causing their symptoms.

Treatment for Cushing’s disease

Your vet will recommend the best treatment options based on your dog’s symptoms, overall health and the type of Cushing’s they have. 

Daily tablets to control your dog’s cortisol levels are the most common treatment, but in some cases, monitoring is considered more appropriate than medication. In rare cases, your dog might need to have the tumour surgically removed. If steroid medication is to blame, your vet will adjust their medication. 

Cushing’s disease usually can’t be cured but it can often be managed with medication, and many dogs with Cushing’s go on to live normal, active lives.

Managing your dog’s Cushing’s disease

Most dogs with Cushing’s will need some form of treatment for the rest of their lives to help manage their symptoms. You’ll need to make sure to give them any regular medication and keep an eye out for new or worsening symptoms. The condition can progress over time, which may require changes to medication dose, so be sure to let your vet know of any changes and take your dog for regular health check ups so your vet can monitor their condition. 

Don’t forget to keep your dog active and happy with their favourite walks and games - they can still enjoy a good quality of life, despite their condition.

Which dogs are at risk of getting Cushing’s disease?

Cushing’s is most common in older dogs, aged 7-12 years. Some studies have found that female dogs are slightly more likely to develop Cushing’s than male dogs, but other studies haven’t found that pattern.

A study by Vet Compass found that Cushing’s was most frequently diagnosed in Jack Russell Terriers, Staffordshire Bull Terriers, Bichon Frise and Border Terriers. They also found a link between Cushing’s and dogs who were overweight for their breed. 

Can you prevent Cushing’s?

There is no way to completely prevent Cushing’s unfortunately, but there are things you can do to keep your dog as healthy as possible as they get older. Give them the best quality of life by making sure they stay at a healthy weight for their breed and attend regular check ups at your vet so any signs of illness can be caught as early as possible.
 

Want information or advice on Cushing’s disease in dogs?

For more information or advice on Cushing’s disease in dogs, contact your local vet.

Find your nearest vet using our Find a Vet page, or speak to a vet online using Online Vets.

Sources

MSD Manual, Cushing Disease (Pituitary-Dependent Hyperadrenocorticism) in Animals

PubMed - Frequency and risk factors for naturally occurring Cushing's syndrome in dogs attending UK primary‐care practices

VetCompass - Cushing’s Diagnostic Prediction Tool