Cushing's Disease, also known as hyperadrenocorticism, predominantly affects middle-aged and older dogs. This endocrine disorder is caused by excessive production of cortisol, typically due to a tumor in the pituitary or adrenal glands. It leads to significant health changes, including increased thirst, appetite, and a pot-bellied appearance. Early detection and management are important for improving the affected dog's quality of life. This guide provides an in-depth look at Cushing's Disease in dogs, from symptoms to treatment options, aiming to inform and assist pet owners in navigating this complex condition.

What is Cushing's disease in dogs?

First, we need to discuss the adrenal glands and their functions. Adrenal glands, located near the kidneys, produce hormones that regulate various bodily processes. One of these hormones is cortisol, often referred to as the "stress hormone" due to its role in managing stress responses. Cortisol also plays a critical role in regulating metabolism, immune function, and blood pressure.

In dogs with Cushing's Disease, there is an excessive production of cortisol from the adrenal glands, causing an imbalance in the body.

There are 3 main types or causes of Cushing's disease in dogs:

  1. Pituitary gland tumor: In dogs, 80-85% of cases of Cushing's disease are caused by a small, benign growth within the pituitary gland in the brain. The result is too much ACTH (Adrenocorticotropic Hormone), boosting cortisol production and release.
  2. Adrenal adenocarcinoma: The other 15-20% of cases are caused by tumors in the adrenal glands, some of which are malignant cancers.
  3. Iatrogenic causes: Lastly, iatrogenic Cushing's syndrome in dogs occurs during prolonged use of glucocorticoid steroids such as prednisone, which increases the amount of cortisol in the body.

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

It is important for dog owners to recognize the clinical signs of Cushing's Disease early on for effective management. The symptoms can vary and may initially be subtle, especially during the early stages of the disease.

However, they tend to become more noticeable as dogs reach middle age and beyond. It is important to closely monitor your pet for any changes that could indicate the onset of this condition.

Common clinical signs of Cushing's Disease in dogs include:

  1. Increased Thirst and Urination: One of the first and most noticeable signs is a significant increase in water consumption and urination. Some dogs may need to go outside more frequently and could potentially have accidents indoors.
  2. Increased Appetite: Dogs with Cushing's Disease often exhibit a heightened appetite and may persistently beg for food.
  3. Hair Loss and Skin Changes: Typical manifestations include thinning of the coat, hair loss, and the development of thin, fragile skin. Hair loss is usually symmetrical and may be accompanied by skin darkening.
  4. Pot-Bellied Appearance: A noticeable distension to the abdomen is a classic sign resulting from the redistribution of fat and muscle loss.
  5. Lethargy and Weakness: Dogs with Cushing's Disease may show reduced energy levels and general weakness.
  6. Recurring Infections: Due to the immunosuppressive effects of excess cortisol, dogs may experience recurrent skin, urinary, or other infections.
  7. Panting: Excessive panting, unrelated to external temperature or physical exertion, is often observed in dogs with Cushing's Disease.

These signs can serve as valuable indicators for you to identify potential issues and seek appropriate veterinary care.

How is Cushing's disease diagnosed?

Diagnosing Cushing's Disease in dogs can be challenging as its symptoms often overlap with other conditions. To confirm the presence of this disease, a comprehensive approach that combines clinical evaluation and specific diagnostic tests is essential.

Here is what you can expect during the diagnostic process for Cushing's Disease:

Veterinary Examination: The first step is a thorough examination by your vet. They will review your dog's medical history and conduct a physical examination. They may ask you about any changes in behavior, appetite, water consumption, or other symptoms you've noticed.

Laboratory Tests: Blood and Urine Tests: These basic tests assess overall health and liver function since Cushing's Disease can impact liver enzymes. Urinalysis helps evaluate kidney function, which can be affected by excessive cortisol levels.

Adrenal Function Tests: If initial tests suggest Cushing's Disease, further evaluation will be necessary to determine the underlying type. These include an ACTH stimulation test or a low-dose dexamethasone suppression test.

Advanced Imaging: An abdominal ultrasound is a valuable tool for examining the adrenal glands, allowing for the detection of tumors or other abnormalities. MRI or CT scans are imaging techniques that aid in the identification and assessment of pituitary tumors, including their size and impact.

During the diagnostic process, it's important for your veterinarian to rule out other diseases that may mimic Cushing's Disease symptoms. Conditions such as diabetes and gastrointestinal disease for example can show similar clinical signs. A comprehensive diagnostic approach ensures accurate identification of the underlying condition.

Please consult with your veterinarian for a proper diagnosis and treatment plan for your furry friend.

What are the treatment options for Cushing's disease in dogs?

Treatment aims to reduce the symptoms of Cushing's Disease and improve the dog's quality of life. This includes managing excessive thirst and hunger, addressing skin issues, and preventing secondary infections.

Treatment options vary depending on whether the disease is caused by a pituitary issue or an adrenal issue.

Medical Management

  • Trilostane (Vetoryl): This medication is commonly used to treat both types of Cushing's Disease. It works by reducing the production of cortisol. The dosage requires careful monitoring and adjustment based on the dog's response and follow-up tests.
  • Mitotane: Primarily used for adrenal-dependent Cushing's Disease, mitotane destroys part of the adrenal gland that produces cortisol. Close monitoring is necessary due to its potent effects and possible side effects. The effects are often irreversible.
  • Ketoconazole: This antifungal medication can also help reduce cortisol production. It can be used when other medications are not suitable. This medication is used very infrequently, however.

Surgical Treatment

  • Adrenal Gland Tumor Removal: If the disease is caused by a tumor in one of the adrenal glands, surgical removal of the affected gland may be recommended. This option is usually considered when the tumor is benign and localized.
  • Pituitary Tumor Treatment: Due to the complexity of the location of the tumor, we typically do not recommend removing pituitary tumors.

Monitoring and Adjustments

Regular monitoring through blood tests and follow-up exams is essential to assess the effectiveness of treatment and make necessary adjustments. This helps monitor cortisol levels and adjust medication dosages.

What is the prognosis for dogs with Cushing's?

The prognosis for dogs with Cushing's Disease depends on the type and response to treatment. With proper care, many dogs live well for years.

  • Pituitary-Dependent Cushing's: Generally the more manageable type with medication.
  • Adrenal-Dependent Cushing's: Good if the tumor is benign and removable. Medication is needed when surgery isn't an option.

What is the life expectancy of dogs with Cushing's disease?

Research studies have shown that in dogs treated with trilostane (Vetoryl®), the median survival time was 900 days. A median survival time of 384 days was reported in a study of 1500 dogs treated with mitotane. Median survival time is the time in which 50% of all patients are still alive after starting therapy.


Cushing's disease is a serious endocrine disorder that affects dogs. The most common way to diagnose Cushing's disease is with the ACTH stimulation test or the Low-Dose Dexamethasone Suppression Test. There is no cure for Cushing's disease in dogs, but it can be managed with daily medication. Treatment options include trilostane, mitotane, and other medications. The life expectancy of dogs with Cushing's disease varies depending on the treatment option chosen, but most dogs will live longer than 900 days when treated with trilostane.

If you have any questions about Cushing's disease in dogs or the treatment options available, please contact your veterinarian. They will be able to provide you with more information and help you decide which treatment is best for your dog.