Cortisol is an essential hormone that helps dogs manage stress, regulate metabolism, and help fight infections. However, when cortisol levels become too high for too long, it can lead to some health problems and make your dog feel unwell.

This condition is called Cushing's disease.

This condition, also called hyperadrenocorticism, is common in middle-aged and senior dogs. This happens when the body produces too much cortisol. Cushing’s disease is progressive, meaning symptoms worsen over time if left untreated. The good news is that dogs with Cushing’s disease can recover.

But first, let’s talk more about Cushing’s disease in dogs.

What are the Types of Cushing’s Disease in Dogs?

In a healthy dog, the body carefully balances cortisol production based on what the dog needs. But in a dog with Cushing’s disease, something goes wrong, leading to their body producing too much cortisol for too long. This creates a whole range of problems for your dog.

There are three main reasons a dog might develop Cushing’s disease.

1. Pituitary-Dependent Cushing’s Disease

This is the most common cause, responsible for about 85% to 90% of all cases. This happens when a tumor forms in the pituitary gland. The pituitary gland controls many hormones, including adrenocorticotropic hormone (ACTH), which tells the adrenal glands how much cortisol to make.

In dogs with pituitary-dependent Cushing’s, the tumor triggers excess ACTH production, which forces the adrenal glands to overproduce cortisol even though the body doesn’t need it.

2. Adrenal-Dependent Cushing’s Disease

This type of Cushing’s disease in dogs is less common. In this type, a tumor forms directly on one of the adrenal glands, causing it to release too much cortisol on its own. These tumors can be benign or malignant. If the tumor is cancerous, it can potentially spread to other parts of the body.

3. Iatrogenic Cushing’s Disease

This form of Cushing’s is caused by long-term use of steroid medications. Some dogs take steroids to manage chronic conditions such as allergies, arthritis, or immune disorders. Since steroids mimic cortisol, prolonged use can lead to excessive cortisol levels. As a result, dogs experience symptoms similar to naturally occurring Cushing’s disease.

Symptoms of Cushing’s Disease in Dogs

Cushing’s disease in dogs develops slowly, which makes it easy to overlook early signs. Many symptoms are also often mistaken for other conditions.

Dogs with Cushing’s disease may show a combination of these common symptoms:

• Increased Thirst and Urination. One of the first signs you will notice is when your dog has increased thirst and urination. If your dog is suddenly emptying the water bowl or having accidents in the house, it could be due to Cushing’s disease.

  
  

• Excessive Hunger. Dogs with Cushing’s disease often seem constantly hungry, even after eating their usual meals. This is because elevated cortisol levels interfere with normal appetites.

  
  

• Lethargy and Weakness. Many dogs with Cushing’s disease become less active and may struggle with routine activities. Even simple activities such as climbing stairs or going on walks may be difficult for dogs. Muscle loss is also common, leading to general weakness.

  
  

• Panting and Respiratory Changes. Excess cortisol can affect breathing, leading to frequent panting, even when a dog is resting. This can be especially noticeable at night or in cooler environments where panting wouldn’t normally occur.

  
  

• Hair Loss and Skin Problems. Dogs with Cushing’s disease often experience thinning hair or patchy hair loss, especially along their sides. Their skin may also become thin, fragile, or prone to infections. Unlike seasonal shedding, this hair loss does not grow back to normal.

  
  

• Pot-Bellied Appearance. One of the most recognizable signs of Cushing’s disease in dogs is a swollen or sagging abdomen. Excess cortisol causes fat to be redistributed and muscle to be wasted. This makes the belly appear distended.

  
  

• Slow Healing and Frequent Infections. Cushing’s disease weakens the immune system of dogs. As a result, dogs become more prone to skin infections, urinary tract infections, and delayed wound healing. If your dog gets infections more frequently than usual, it could be a sign of an issue with hormonal imbalance.

  
  

• Behavioral Changes. Some dogs may show restlessness, anxiety, or difficulty sleeping. Increased cortisol levels can also make them more irritable or reactive to sounds that didn’t bother them before.

How is Cushing’s Disease in Dogs Diagnosed?

Cushing’s disease in dogs develops gradually and shares symptoms with other conditions. So, it's important to use a combination of blood tests and imaging techniques to rule out the condition. 

Here are the tests and methods we use to diagnose Cushing’s disease in dogs:

Vet Assessment

The first step in diagnosing Cushing’s disease in dogs is a thorough checkup of the present symptoms. Because other health issues can cause these symptoms, we will move on to lab tests to get a clearer picture.

Blood and Urine Tests

We’ll run routine bloodwork and a urinalysis to check for abnormalities related to Cushing’s disease in dogs. The signs will include elevated liver enzymes, high cholesterol, changes in white blood cell count, and diluted urine.

Imaging Tests

Ultrasounds can help assess the condition of your dog’s adrenal glands, liver, kidneys, and possible tumors. MRIs and CT scans can check a pituitary tumor in the brain.

Hormone Tests for Cushing’s Disease

Standard bloodwork isn’t enough to confirm Cushing’s disease in dogs, so vets use specific hormonal tests. These will check cortisol regulation. These are the ACTH stimulation test and the low-dose dexamethasone suppression test. 

For an ACTH stimulation test, a blood sample will be taken. We will follow up on this with an ACTH injection. Another blood sample will be taken after an hour to measure cortisol levels. If cortisol levels are high, the results suggest Cushing’s disease in dogs.

The second method also starts with a blood sample, then an injection of dexamethasone. Blood samples will be collected four and eight hours after the time of injection. In healthy dogs, cortisol levels should drop significantly. In dogs with Cushing’s disease, cortisol remains high.

Treatment for Cushing’s Disease in Dogs

Once a dog has been diagnosed with Cushing’s disease, the next step is deciding on the best treatment plan. The approach will depend on whether it's pituitary-dependent, adrenal-dependent, or caused by long-term steroid use.

While Cushing’s disease cannot be completely cured, it can be managed effectively. Here’s how we do it:

Medical Management

For dogs with pituitary-dependent Cushing’s disease, medication is usually the best option. Trilostane and mitotane are two of the most commonly used medications to help manage your dog’s Cushing disease. These medications help to reduce cortisol production, helping bring hormone levels back to normal. Regular monitoring and blood tests will be observed because these medications can be strong.

Surgery

Surgery within the area of the pituitary gland is risky, so this option is more suited for dogs with adrenal-dependent Cushing’s disease. The tumor along the adrenal gland will be located and surgically removed. Additional treatment such as chemotherapy will be used if needed.

Adjusting Steroid Use

If Cushing’s disease is caused by long-term steroid use, the best approach is to gradually reduce the medication. However, veterinary guidance must be observed. Stopping steroids suddenly can cause serious withdrawal symptoms, so the dose must be slowly tapered over time. 

In some cases, the dog’s adrenal glands may struggle to function properly after long-term steroid use. As a result, additional treatment might be required.

Supportive Care and Lifestyle Management

Regardless of the type of Cushing’s, managing the disease requires constant monitoring and management. These will include:

• Regular vet visits. Cushing’s disease requires lifelong monitoring to ensure your dog’s medication is working properly. Blood tests and medication adjustments will be done during your dog’s visits in order to help manage its condition.
  
  

• Dietary Adjustments. A healthy diet with high-quality protein and limited fats will be used to support metabolism. Avoid foods high in sodium. Make sure to 
  
  

• Regular Exercise. Moderate exercise will be important to maintain muscle strength without overexertion. Short walks on a consistent schedule can be a great start.
  
  

• Monitoring. Watching for complications like infections, canine diabetes, or high blood pressure will be a part of your daily routine.

A healthy dog is a happy dog, and a happy dog makes life brighter. Care for them, love them, and they’ll give you a lifetime of loyalty in return.

- Dr. Soheyl Simaei

FAQs About Cushing’s Disease in Dogs

1. Is Cushing’s disease in dogs life-threatening?

If it’s left untreated, Cushing’s disease can be life threatening for dogs. This can result in serious health conditions such as diabetes, infections, high blood pressure, and organ failure.

2. What is the life expectancy of dogs with Cushing’s disease?

On average, dogs live 2 to 3 years after diagnosis. Only a small percentage reach 4 years and more with proper treatment. 

3. What is the best diet for dogs with Cushing’s disease?

A diet consisting of high-quality protein and low fat is a good start. Also, make sure it is low in sodium and avoid processed foods.

Conclusion

Cushing’s disease in dogs can be somewhat of a silent intruder. The condition can cause subtle symptoms that can be mistaken for other health conditions. This makes it super important to head right to the clinic once you’ve noticed a couple of these signs.

While Cushing’s disease can go unnoticed, there are ways to help give your dog a happy and comfortable life. With consistent monitoring and care, many dogs live for years after diagnosis with a good quality of life.