Vet Reviewed

By Carmela Ciuraru | October 31, 2023

Cushing’s disease (or Hyperadrenocorticism) is an endocrine disorder that occurs commonly in middle-aged or senior dogs, causing harmful overproduction of cortisol in the body. As in humans, cortisol is an important hormone that, when functioning normally, serves as a stress response, affects metabolism and weight gain, and helps regulate blood sugar levels. 

When there’s too much cortisol in the body, this weakens the immune system and causes other complications, leaving a dog more vulnerable to infections and diseases. Unfortunately, dogs with Cushing’s disease have an increased risk for developing bladder stones, diabetes, pulmonary thromboembolism, urinary tract infections, congestive heart failure, and more.

The prognosis for dogs with Cushing’s disease depends on the dog’s age and overall health, as well as which kind of Cushing’s disease is present. Most often, it is managed through medication and close monitoring by your dog’s vet. Talk with your vet along the way about how you can best support your dog’s quality of life.

What causes Cushing’s disease in dogs?

The causes for Cushing’s disease in dogs stem from either pituitary or adrenal gland malfunction. The majority (close to 90%) of Cushing’s cases are rooted in pituitary issues—triggered by a tumor on the pituitary gland. A pea-sized gland at the base of the brain, the pituitary gland plays a critical role in the endocrine system.

This gland produces several hormones that help control other organs and body functions, including adrenocorticotropic hormone (ACTH). When a pituitary tumor forms, it leads to the overproduction of ACTH, which then travels through the bloodstream to the adrenal glands, stimulating them to produce more cortisol than the body needs.

When the cause of Cushing’s is adrenal-based, there’s a tumor in the adrenal glands. Your dog has two adrenal glands, small glands in the abdomen that sit atop the kidneys. (Tumors usually affect only one gland rather than both.) Not all tumors are cancerous, but even benign tumors in the adrenal glands can be active hormonally. However, fewer than twenty percent of dogs develop adrenal-based Cushing’s disease.

The third type, known as iatrogenic Cushing’s disease, is caused by excessive use of injectable oral, or topical steroid medications. Of course, vets prescribe steroids when they are essential to a patient’s care—but sometimes, however necessary, long-term overuse can prove harmful.

What are some signs and symptoms of Cushing’s disease?

  • Excessive thirst, increased water consumption 
  • Need to urinate more frequently
  • Increase in appetite
  • Increased incidence of urinary tract infections
  • Increased risk of bacterial skin infections
  • Excessive panting, even while at rest
  • Pot belly (enlarged abdomen)
  • Muscle weakness 
  • High blood pressure
  • Lethargy

Note that not all dogs display clinical signs of Cushing’s disease in the same way. In general, it’s good to note any drastic and concerning changes in your dog’s habits and report them to your vet. (Never dismiss changes in appetite, urination, or thirst by assuming these things happen simply because your dog is getting older.) If you see that your dog is suddenly very thirsty all the time, excessively hungry at mealtime, and needs to urinate more frequently, these are common signs of Cushing’s disease. But only a vet can help you determine what’s going on, and the best course of action to take.

How can I prevent Cushing’s disease in my dog?

Unfortunately, there is no way to protect your dog from getting Cushing’s disease, as it occurs naturally, and can depend partly on the breed, and genetic predisposition. For instance, Cushing’s is more prevalent in breeds such as poodles, dachshunds, Yorkshire terriers, Boston terriers, and German shepherds.

How is Cushing’s disease diagnosed and treated?

Before diagnosing a dog with Cushing’s disease, veterinarians will first want to rule out health problems. They conduct blood tests, and other screenings such as a urinalysis, as well as imaging scans, to diagnose Cushing’s. If the vet suspects the origin of Cushing’s is adrenal-dependent, they will typically do an abdominal ultrasound to detect the presence of adrenal gland tumors. In some cases, the vet will need to do chest and abdomen X-rays to check whether there are tumors elsewhere in the body.  

Along with other factors, the type of Cushing’s disease (adrenal-based or pituitary) is important, and will determine what course of treatment is prescribed by your vet. Each kind has a different treatment and a different prognosis. (If the cause is iatogenic, steroid medication dosages will be stopped, in a controlled and gradual manner, to reduce the severity of symptoms.)

Most vets will treat either form with medication to help manage the disease. Some medications work to suppress cortisol; others help manage blood pressure or serve to block different hormone receptors. 

Unfortunately, the only hope for a cure is when the disease is adrenal dependent and the tumor has not yet spread. In these cases, the tumor can be surgically removed, but surgery is not an option for all dogs. You can talk with your vet to inquire about any holistic or natural treatments to consider.

Otherwise, Cushing’s is a lifelong condition that can only be managed by medication rather than cured. It’s an insidious disease. The prognosis varies, with some dogs living just a few years with Cushing’s, and others living longer. Because the disease occurs commonly in older dogs, there may be other (unrelated) health complications impacting a dog’s lifespan.

You can help your dog live more comfortably with Cushing’s disease through diligent care, which includes close monitoring from the vet (regular blood work and medical checkups), keeping up with medication consistently as directed, and watching out for harmful side effects or complications in case dosage adjustments are needed. Following your vet’s guidance is the best thing you can do for your dog.