Cushing’s disease in dogs: FAQ

What is Cushing’s disease?

Cushing's disease (hyperadrenocorticism) is a condition where the body overproduces the cortisol steroid hormone. The condition is more common in middle aged and older dogs.

What causes Cushing's disease in dogs?

Dogs normally need some steroids for their bodies to function properly. These are produced by the adrenal gland, which sits next to the kidney. The adrenal gland is sent messages to produce cortisol by the pituitary gland, which sits at the base of the brain. If a dog gets a growth on either of these glands, this can send hormone production into overdrive which leads to a number of symptoms.

The majority of Cushing’s cases are caused by a benign (non-cancerous) tumour on the pituitary gland. Tumours on the adrenal gland can also cause this disease, but this is less common. High level use of steroids, used to treat immune disorders or allergies, can also mimic the symptoms of Cushing’s disease. Gradual weaning off the drug can reverse the symptoms.

How does Cushing’s disease affect dogs?

Cortisol is essential to the day to day running of the body. It increases in times of stress. Cortisol tells the body it is about to have to work quickly to fight off the cause of the stress. A dog’s body reacts to this by speeding up the metabolism and releasing energy in the form of fat and sugar, and holding on to water. This is a natural response to a stressor in a healthy dog during stressful moments.

In a dog with Cushing’s disease, too much cortisol is being produced. Over time, this can cause changes which may make the dog prone to health problems. This can include skin changes and infections, or they may become more prone to diabetes.

What are the symptoms of Cushing’s disease in dogs?

Common signs of Cushing's disease in dogs include:

• excess thirst 
• excessive urination (eg your dog suddenly begins needing to go out to the toilet in the middle of the night)
• hair loss
• weight gain
• panting
• skin changes
• abdominal swelling, which can make the belly appear to sag
• a lack of energy

There are also other diseases with these signs in common, so getting a diagnosis can be challenging. To get a definitive diagnosis, speak to your vet.

How is Cushing's diagnosed in dogs?

There is not a simple test that can diagnose Cushing's disease in dogs. Since the symptoms are similar to other conditions, it can take time to diagnose. Dogs with other health issues are also more likely to test positive, even if they do not actually have Cushing's disease.

Your vet will look at your dog's symptoms and health history as a whole. They will then do a physical full body check. A blood sample and urine sample may also be needed, along with other tests.

How is Cushing's treated in dogs?

Treatment for Cushing's disease can have some risks, so it's not always advised to treat it. Your vet will advise you if treatment is right for your dog, and which type is the most suitable, after weighing up the risks and benefits.

Medication

Treatment for Cushing’s disease depends on the type your dog has. But medication (in the form of tablets) can be used in most cases. If your dog has mild symptoms, medicine may not be necessary, but your vet will closely monitor your dog. 

Surgery

Surgery is usually a specialist option. It's used to remove the tumour that is causing Cushing's. But surgery is a costly procedure. In some cases, further tumours can spread through the body. In severe cases, it can be untreatable.

Reducing steroids

If your dog has developed Cushing’s due to taking steroids for other health conditions (such as allergies or immunity issues) your vet will advise you to wean your dog off steroids. Coming off steroids too quickly can lead to further, potentially-fatal, problems. Your vet will advise you on the process of reducing steroids slowly.

Managing Cushing’s in dogs

While Cushing’s disease cannot be cured, it can be managed in most cases. But it's costly and requires commitment.
If your dog is being treated for Cushing’s with tablets, you'll need to give them to your dog for the rest of their life. Your dog will also need to visit your vet regularly, as treatment needs careful monitoring. This often includes regular blood tests.

Without careful management (and sometimes even with management) of the condition, your dog's symptoms will worsen over time. They may become more lethargic and prone to infection. This can impact their quality of life.