The most common symptoms of Cushing’s disease in dogs are excessive drinking, frequent urination, increased appetite, a pot-bellied appearance, and hair loss. These signs develop gradually, often over months, which is why many owners initially chalk them up to normal aging. Cushing’s disease (hyperadrenocorticism) occurs when a dog’s body produces too much cortisol, a stress hormone that, in excess, disrupts nearly every system in the body. It predominantly affects middle-aged to older dogs between 7 and 12 years old.
Excessive Thirst and Urination
The earliest and most noticeable symptom is usually a dramatic increase in water intake and urination. Your dog may drain the water bowl multiple times a day, need to go outside far more often, or start having accidents in the house despite years of reliable housetraining. Normal water intake for a dog is roughly 50 to 60 ml per kilogram of body weight per day. In dogs with Cushing’s, intake can exceed 90 to 100 ml per kilogram, effectively doubling. Even if your dog’s drinking doesn’t hit that clinical threshold, a clear increase from their normal baseline is meaningful.
The increased urination follows directly from the increased drinking. Dogs may produce large volumes of dilute urine, and overnight accidents become common. Many owners first suspect a urinary tract infection, which is a reasonable thought since Cushing’s dogs are also genuinely prone to UTIs (historically reported in 39 to 50% of affected dogs, though more recent research suggests the rate may be lower).
Increased Appetite
Cortisol ramps up appetite significantly. Your dog may act ravenous, beg constantly, steal food, or seem unsatisfied after meals. This is one of the symptoms owners often dismiss, assuming their dog is just being greedy or that their metabolism has changed with age. But a sudden, persistent increase in hunger, especially combined with increased thirst, is a strong signal that something hormonal is going on.
The Pot-Bellied Appearance
A sagging, distended belly is one of the most recognizable physical signs of Cushing’s disease. It happens for two reasons working together. Excess cortisol weakens the abdominal muscles over time, causing them to lose tone. Simultaneously, cortisol promotes fat redistribution toward the abdomen and causes the liver to enlarge. The result is a dog that looks bloated or barrel-shaped, even if they haven’t gained significant weight overall. This change tends to develop slowly enough that owners may not notice until it’s quite pronounced, especially in breeds that already carry weight in the midsection.
Skin and Coat Changes
Cortisol has a pronounced effect on skin health. Hair loss is extremely common, and it follows a distinctive pattern: symmetrical thinning on both sides of the body, typically along the flanks, abdomen, and trunk. The head and legs are usually spared. Hair that’s clipped or shaved may grow back very slowly or not at all.
The skin itself often becomes noticeably thinner, almost papery, and bruises more easily. You might see darkened patches of skin (hyperpigmentation), blackheads, or recurrent skin infections that don’t respond well to treatment. In more advanced cases, some dogs develop hard, calcified deposits in the skin called calcinosis cutis, which look like raised, white or grayish plaques. These can be uncomfortable and are one of the more distinctive signs of chronic cortisol excess.
Panting and Exercise Intolerance
Excessive panting, even at rest or in cool environments, is a hallmark of Cushing’s. Cortisol affects metabolism, muscle mass, and fat distribution in ways that make it harder for dogs to regulate their body temperature and exert themselves comfortably. Weakened respiratory muscles, combined with abdominal fat pressing on the diaphragm, contribute to the heavy breathing.
You may also notice your dog tiring more quickly on walks, lagging behind, or simply being less willing to play. Muscle wasting occurs because cortisol breaks down protein in muscle tissue, reducing strength and endurance. Dogs that were once active may become lethargic and reluctant to jump onto furniture or climb stairs.
Recurrent Infections
Chronically elevated cortisol suppresses the immune system. Specifically, it inhibits the ability of infection-fighting white blood cells to migrate to affected areas, leaving the body less equipped to fight off bacteria and other pathogens. This makes dogs with Cushing’s unusually prone to urinary tract infections, skin infections, and ear infections that keep coming back despite treatment. If your dog seems to cycle through infections that clear up only to return weeks later, that pattern alone warrants investigation.
Breeds Most at Risk
Cushing’s disease has two main forms. About 80 to 85% of cases are pituitary-dependent, caused by a small tumor on the pituitary gland in the brain. This form is more common in smaller breeds, including Miniature Poodles, Dachshunds, Yorkshire Terriers, Bichon Frises, Jack Russell Terriers, Miniature Schnauzers, Lhasa Apsos, and Staffordshire Terriers. The remaining cases are adrenal-dependent, caused by a tumor on one of the adrenal glands, and this form is more common in larger breeds like German Shepherds.
Interestingly, some breeds appear to be at lower risk: Golden Retrievers, Labrador Retrievers, Border Collies, and Cocker Spaniels are among the least commonly affected. A third form, iatrogenic Cushing’s, isn’t a spontaneous disease at all. It develops in dogs that have been on steroid medications (like prednisone) for extended periods. The symptoms look identical, but they resolve when the medication is gradually tapered.
How Symptoms Develop Over Time
What makes Cushing’s tricky to catch early is that symptoms creep in one at a time over weeks or months. The drinking and urination usually come first, followed by appetite changes and weight redistribution. Skin and coat changes tend to appear later, and muscle wasting and exercise intolerance develop as the disease progresses. Many owners look back and realize the signs were there for six months or more before they connected the dots.
Because each symptom on its own can have many explanations, it’s the combination that matters. A middle-aged or older dog that’s drinking excessively, losing hair symmetrically, developing a potbelly, and panting more than usual is presenting a pattern that points strongly toward Cushing’s.
What Testing Looks Like
If your vet suspects Cushing’s based on symptoms, the first step is usually blood work. A liver enzyme called alkaline phosphatase (ALP) is elevated in 83 to 100% of dogs with Cushing’s, so a high ALP level is a strong clue, though it can also be elevated by other illnesses and stress.
From there, specific hormone tests are used to confirm the diagnosis. The two most common are the ACTH stimulation test and the low-dose dexamethasone suppression test. Each has tradeoffs. The ACTH stimulation test is faster and simpler but can miss up to 41% of cases caused by adrenal tumors. The dexamethasone suppression test is more sensitive overall but can produce false positives in dogs that are stressed or have other illnesses like uncontrolled diabetes. A urine cortisol-to-creatinine ratio is sometimes used as a screening tool; it’s very good at ruling Cushing’s out when the result is normal, but a high result doesn’t confirm the disease on its own because many other conditions can cause elevated readings.
Diagnosing Cushing’s often takes more than one test and one visit. Your vet may need to run multiple tests and imaging to determine both whether your dog has the disease and which form it is, since that affects the treatment approach.