Cushing’s Disease in Dogs: Natural vs. Iatrogenic
Is your dog suddenly drinking the water bowl dry, asking to go outside all night, or developing a pot-bellied appearance? It might not just be aging—it could be Cushing’s disease.
What is Cushing’s Disease?
Cushing’s disease, also called hyperadrenocorticism, occurs when a dog’s body produces too much cortisol over time.
Cortisol is a normal hormone that helps regulate:
- Stress response
- Immune function
- Metabolism
But in excess, it slowly wreaks havoc on the body including causing cataracts, muscle weakness, ligament weakness, bacterial skin infections, and predisposes to diabetes.
Two Main Types of Cushing’s in Dogs
1. Naturally Occurring Cushing’s Disease: This is the most common form and happens due to internal disease processes.
There are two subtypes:
- Pituitary-dependent Cushing’s (PDH)-more common in smaller dogs
- Accounts for ~80–85% of cases
- Caused by a small tumor in the pituitary gland
- Leads to overstimulation of the adrenal glands
- Adrenal-dependent Cushing’s (ADH)-more common in large breed dogs
- Caused by a tumor in one of the adrenal glands
- Can be benign or malignant
2. Iatrogenic Cushing’s Disease-“Iatrogenic” means caused by medical treatment.
This occurs when dogs are given long-term or high-dose steroids, such as:
- Prednisone
- Dexamethasone
These medications are commonly used for:
- Allergies
- Autoimmune diseases
- Chronic inflammation
Over time, excess external steroids mimic the effects of naturally high cortisol levels.
Common Signs to Watch For
Cushing’s disease develops gradually, so signs can be subtle at first.
Classic symptoms include:
- Increased thirst (polydipsia)
- Increased urination (polyuria)
- Increased appetite (polyphagia)
- Panting
- Thin skin
- Hair loss (especially along the body, not the head/legs)
- Pot-bellied appearance
- Muscle weakness
Pro tip for listeners:
If your dog suddenly seems like they’re “aging overnight,” Cushing’s should be on the radar.
How is It Diagnosed? Diagnosis can be tricky—it’s rarely just one test.
Veterinarians may use:
- Bloodwork (often shows elevated liver enzymes)
- Urine testing
- ACTH stimulation test
- Low-dose dexamethasone suppression test
- Ultrasound to evaluate adrenal glands
Treatment Options
For Naturally Occurring Cushing’s:
- Medical management is most common
- Medications like trilostane or mitotane
- Surgery may be an option in select adrenal tumor cases
For Iatrogenic Cushing’s:
- Gradual reduction of steroid use
- Never stop steroids abruptly—this must be done carefully under veterinary supervision
Prognosis
With proper treatment:
- Many dogs live happy, comfortable lives for years
- Regular monitoring is essential
Untreated, however, Cushing’s can lead to:
- Diabetes
- High blood pressure
- Increased risk of infections
- Blood clots
Cushing’s disease is one of those conditions that can sneak up on pet owners—but once you know the signs, it becomes much easier to catch and manage.
If your dog is drinking more, eating more, and just not quite themselves, don’t chalk it up to “just getting older.” It might be time for a conversation with your veterinarian.
Mixed breed dog with pendulous abdomen due to Cushing’s disease
Miniature schnauzer with truncal hair loss due to Cushing’s disease