Several conditions in dogs produce symptoms nearly identical to Cushing’s disease, including excessive drinking, hair loss, a pot belly, and panting. This overlap is common enough that more than 50% of dogs with a non-adrenal illness will actually test positive on one of the standard Cushing’s screening tests, the low-dose dexamethasone suppression test. Understanding what else can cause these signs helps you ask better questions at the vet and avoid a misdiagnosis that leads to unnecessary treatment.
Iatrogenic Cushing’s: The Most Direct Mimic
The condition most perfectly identical to Cushing’s disease isn’t a mimic at all. It’s the same syndrome triggered by medications rather than a tumor. When dogs receive corticosteroids, whether oral, injectable, or even topical, their bodies respond to the flood of external cortisol the same way they’d respond to excess cortisol from a tumor. The drinking, urinating, hunger, hair thinning, pot belly, and muscle wasting all develop on the same timeline.
What catches many owners off guard is how little steroid exposure it takes. There’s a documented case of a dog developing full-blown Cushing’s syndrome from a topical corticosteroid cream the owner was using on the dog’s skin. Eye drops, ear medications, and skin sprays containing steroids can all contribute if used long enough. If your dog is showing Cushing’s-like symptoms and has been on any steroid product, even something that seems minor, that’s the first thing your vet needs to know. The fix is straightforward: a careful, gradual taper off the medication, after which symptoms resolve.
Liver Disease and the Pot Belly Problem
Cushing’s disease causes a distinctive pot-bellied appearance from a combination of an enlarged liver, weakened abdominal muscles, and fat redistribution. The trouble is that primary liver disease creates a strikingly similar picture. Dogs with liver problems develop hepatomegaly (an enlarged liver you can feel through the belly wall), and on bloodwork, the most consistent finding in Cushing’s patients is elevated alkaline phosphatase (ALP), the same liver enzyme that rises in dogs with primary liver or gallbladder disease.
ALP also climbs in older dogs, overweight dogs, and dogs under physiological stress from other illnesses. This is where misdiagnosis often starts: a vet sees a middle-aged dog with a big belly and high ALP, and Cushing’s testing gets ordered. But elevated ALP without the classic constellation of other Cushing’s signs, like increased thirst, frequent urination, and skin changes, shouldn’t trigger a Cushing’s workup on its own. If your dog has high ALP but otherwise seems normal, liver-specific testing and imaging are a more logical next step than Cushing’s screening.
Hypothyroidism and Diabetes
Both hypothyroidism (low thyroid function) and diabetes mellitus share significant symptom overlap with Cushing’s. Hypothyroid dogs often develop symmetrical hair loss, weight gain, lethargy, and skin infections, all of which appear in Cushing’s patients too. The key difference is that hypothyroid dogs tend to gain weight and become sluggish, while Cushing’s dogs typically maintain a ravenous appetite with muscle wasting rather than true fat gain, and they’re often restless rather than lethargic.
Diabetes and Cushing’s share an even tighter overlap. Both cause dramatically increased thirst, frequent urination, and a big appetite. In fact, Cushing’s disease frequently causes insulin resistance, so the two conditions sometimes exist together in the same dog. When they do, diabetes that’s unusually hard to control with insulin can be the first clue that Cushing’s is lurking underneath. If your dog has been diagnosed with diabetes but blood sugar remains stubbornly high despite escalating insulin doses, Cushing’s testing is warranted.
Alopecia X: The Cosmetic Lookalike
Alopecia X is a hair loss condition seen most often in Nordic breeds like Pomeranians, Samoyeds, and Alaskan Malamutes. The pattern of fur loss looks remarkably like Cushing’s: symmetrical thinning along the trunk, with the head and lower legs spared. The caudal thighs (the back of the hind legs) are often affected too. Skin biopsies aren’t much help, because the microscopic changes are nonspecific and compatible with any endocrine skin disorder, including Cushing’s.
The critical difference is that dogs with Alopecia X have no other Cushing’s symptoms. They don’t drink excessively, they don’t have a pot belly, they don’t pant constantly, and their muscle tone stays normal. Their ACTH stimulation tests and low-dose dexamethasone suppression tests come back normal. Alopecia X is essentially a diagnosis of exclusion: the hair loss looks endocrine, but once you’ve ruled out Cushing’s, hypothyroidism, sex hormone imbalances, and other causes, what remains is Alopecia X. It’s a cosmetic problem, not a dangerous one.
Atypical Cushing’s: When Standard Tests Miss It
Some dogs show every clinical sign of Cushing’s, including elevated ALP, but their cortisol levels test completely normal on both standard screening tests. This is sometimes called atypical hyperadrenocorticism. In these cases, the adrenal glands are overproducing sex hormones and hormone precursors rather than cortisol itself. The hormones involved include progesterone, estradiol, androstenedione, and a progesterone derivative called 17-hydroxyprogesterone.
In a study of dogs with atypical Cushing’s, post-stimulation androstenedione levels reached a median of 5.89 ng/mL, well above the normal upper limit of 3.97 ng/mL. Progesterone and 17-hydroxyprogesterone similarly exceeded reference ranges after stimulation. Diagnosing this form requires a specialized adrenal hormone panel that measures these sex hormones before and after stimulation, something most general practice vets don’t run as a first step. If your dog’s symptoms strongly suggest Cushing’s but standard cortisol testing is negative, ask about an expanded adrenal panel.
Other Conditions That Cause Similar Signs
Chronic panting, one of the hallmark Cushing’s signs, has a long list of other causes. Heart disease, chronic pain, anxiety, respiratory problems, and obesity can all produce persistent panting that looks like the cortisol-driven panting of Cushing’s. Panting alone, without increased thirst and skin or coat changes, is rarely Cushing’s.
Chronic urinary tract infections, another frequent Cushing’s finding, also occur independently in older female dogs and dogs with bladder stones or anatomical issues. Recurrent skin infections happen in dogs with allergies, immune problems, or poor grooming. Each of these symptoms in isolation has many possible explanations. What makes Cushing’s distinctive is the combination: a dog who drinks and urinates excessively, pants at rest, develops a sagging belly with visible muscle loss, and has thinning skin or fur, often with recurrent infections layered on top.
Why False Positives Are So Common
The standard screening tests for Cushing’s are designed to be sensitive, meaning they’re good at catching true cases but tend to flag dogs who don’t actually have the disease. The low-dose dexamethasone suppression test produces false positives in more than half of dogs with non-adrenal illnesses. Any significant stress or concurrent disease can elevate cortisol enough to trigger a positive result. A dog with uncontrolled diabetes, a serious infection, or even the stress of a vet visit can test positive without having Cushing’s at all.
This is why veterinary endocrinologists emphasize that Cushing’s testing should only be pursued in dogs with multiple compatible clinical signs. Testing a dog simply because one blood value is off, or because they’re drinking a bit more water than usual, dramatically increases the chance of a false positive that leads to unnecessary (and potentially harmful) treatment. The best protection against misdiagnosis is a vet who looks at the full clinical picture before reaching for a screening test.