Cushing’s disease in dogs is not contagious. It cannot spread between dogs, from dogs to humans, or from humans to dogs. Cushing’s is a hormonal disorder caused by the body producing too much cortisol, typically because of a tumor in the pituitary gland or adrenal glands. There is no virus, bacterium, or parasite involved, so there is zero transmission risk to other pets or people in your household.
Why Cushing’s Can’t Spread
Cushing’s disease belongs to a category called endocrine (hormonal) disorders. The underlying problem is internal: a dog’s own body overproduces cortisol, the hormone responsible for regulating metabolism, stress response, and immune function. In about 85% of naturally occurring cases, a small, usually benign tumor on the pituitary gland in the brain sends excessive signals to the adrenal glands, telling them to pump out more cortisol than the body needs. In the remaining 15%, a tumor grows directly on one or both adrenal glands (located near the kidneys) and produces excess cortisol on its own.
Because the disease originates from a tumor or hormonal malfunction inside an individual dog, it has no infectious component. You can safely house a dog with Cushing’s alongside other pets without any concern about spreading the condition.
A Third Form From Medication
There is also a form called iatrogenic Cushing’s syndrome, which develops when a dog receives steroid medications (like those prescribed for allergies or inflammation) for an extended period. The external steroids flood the body with cortisol, mimicking the effects of a tumor-driven case. This form resolves when the medication is gradually tapered off under veterinary guidance. Again, it has nothing to do with infection.
Signs to Recognize
Cushing’s disease tends to develop slowly, and the early signs often look like normal aging. The most common symptoms include drinking much more water than usual, needing to urinate frequently (including accidents in housetrained dogs), increased appetite, a pot-bellied appearance, hair loss or thinning coat, and skin that seems fragile or slow to heal. Dogs may also pant more, seem lethargic, or develop recurring skin infections because excess cortisol weakens the immune system.
These symptoms overlap with other conditions, which is why Cushing’s can be tricky to identify. Most dogs are diagnosed around age 10 or older.
Breeds at Higher Risk
Any dog can develop Cushing’s, but certain breeds are significantly more prone. A large UK study found that Bichon Frises had about six times the odds of developing the disease compared to mixed-breed dogs. Border Terriers were close behind at roughly five times the odds, followed by Miniature Schnauzers at about three times the odds. Lhasa Apsos, Yorkshire Terriers, Staffordshire Bull Terriers, and Jack Russell Terriers also showed elevated risk. If you own one of these breeds, it’s worth keeping the symptoms on your radar as your dog ages.
How It’s Diagnosed
Diagnosis usually starts with blood work and a urine sample, but confirming Cushing’s requires specialized hormone testing. The preferred initial test is the low-dose dexamethasone suppression test, which measures how a dog’s cortisol levels respond over eight hours after receiving a small injection. A second option, the ACTH stimulation test, checks how the adrenal glands respond to a hormone signal. This test is also used to monitor treatment once a dog has been diagnosed and to identify the iatrogenic (medication-caused) form. Abdominal ultrasound or advanced imaging may follow to locate a tumor.
Treatment and Outlook
Most dogs with Cushing’s are managed with daily oral medication rather than surgery. The two main drug options work differently but produce similar survival outcomes. One destroys a portion of the adrenal gland tissue, while the other blocks cortisol production without damaging the glands. A study comparing the two in dogs with adrenal tumors found median survival times of about 15.6 months and 14 months, respectively, with no statistically significant difference. The drug that blocks cortisol production tends to cause fewer and milder side effects, so it is commonly chosen as the first-line treatment.
Treatment doesn’t cure the underlying tumor, but it brings cortisol levels back to a healthy range. Dogs on medication need regular blood tests (typically every few months) to make sure the dose is keeping cortisol properly controlled. Most owners notice improvements within weeks: less excessive drinking, fewer accidents, better energy, and gradually improved coat quality.
For adrenal tumors specifically, surgical removal is sometimes an option. About half of adrenal tumors are benign and half are malignant, so the decision depends on tumor size, location, and whether it has spread. Pituitary tumors are rarely removed surgically in dogs, though radiation therapy is available at some specialty centers.
Living With a Dog Who Has Cushing’s
Dogs with well-managed Cushing’s can maintain a good quality of life for months to years after diagnosis. The condition requires ongoing monitoring, but the day-to-day routine is straightforward: medication given at home, periodic vet visits for blood work, and keeping an eye out for returning symptoms that might signal a dose adjustment. Because Cushing’s suppresses the immune system, watch for skin infections or wounds that heal slowly, and keep up with regular veterinary checkups. Your other pets, your family members, and any visiting animals are completely safe around a dog with this condition.