Cushing's Disease in Dogs: Symptoms and Stages

A dog with Cushing's disease usually drinks and urinates far more than normal, eats as though it has never been fed, pants heavily when nothing has happened to justify it, develops a sagging pot-bellied abdomen, thins out through the coat and skin, and loses muscle over the spine, skull and hind legs. If you are seeing several of those changes in a middle-aged or older dog, book a veterinary appointment, because these signs overlap with several other serious conditions and only testing can tell them apart. Seek emergency care immediately, rather than waiting for a routine slot, if your dog collapses, struggles to breathe, retches without bringing anything up, develops a hard and painful swollen belly, stops eating, or becomes suddenly weak.

Cushing's disease, known medically as hyperadrenocorticism, describes a body exposed to too much cortisol for too long. Cortisol is a normal and necessary hormone. It mobilises energy, dampens inflammation and helps a dog cope with stress. In the right amount, over a short window, that is useful. Sustained at a high level month after month, it quietly reshapes a dog: it breaks protein down faster than the body rebuilds it, pushes fat toward the abdomen, thins the skin, weakens muscle, blunts immune defences and drives thirst. Nearly every symptom below traces back to that single surplus.

The surplus can come from a small growth on the pituitary gland that keeps telling the adrenal glands to produce, from a growth on an adrenal gland itself, or from long-term steroid medication given for an unrelated problem. These are different situations with different management, and the difference is settled by veterinary testing, not by observation at home. If your dog is on a prescribed steroid, never stop or reduce it yourself. Talk to your vet about whether the medication is playing a role and how any adjustment should be made.

The signs owners usually notice first

This condition rarely arrives. It accumulates. Most owners can only identify the start of it in hindsight, which is why the early picture is so often filed under getting older.

Drinking and urinating much more. This is the change that sends most owners to the clinic. The water bowl empties faster, the dog asks to go out overnight, and a reliably house-trained dog may start having accidents or leaving a damp patch in its bed. Excess cortisol interferes with the kidneys' ability to concentrate urine, so the dog loses more water and has to drink to keep up.

A relentless appetite. Counter-surfing, bin-raiding, scavenging on walks, begging from a dog that never begged. Cortisol is a hunger signal, and dogs with high levels often act genuinely driven rather than merely greedy.

Panting at rest. Heavy or frequent panting in a cool room, after no exercise, sometimes worst at night, is one of the most characteristic complaints. Research suggests several overlapping reasons: weakening of the respiratory muscles, fat laid down inside the chest and abdomen, an enlarged liver pressing forward against the diaphragm, and cortisol's own effect on the brain's breathing drive. Panting on its own is not diagnostic of anything, but panting alongside thirst and a changing body shape is worth an appointment.

Lower stamina and more sleeping. Shorter walks, reluctance on stairs, hesitation before jumping onto the sofa or into the car, a slower rise from lying down. This stems from real muscle loss, not simply from a lack of interest.

Infections that keep coming back. Recurrent urinary tract infections, skin infections that clear on medication and return weeks later, or ear problems in a dog with no previous history. Cortisol suppresses the immune response and can also mask the usual signs of infection, so a urinary infection may be present with little straining or discomfort.

Restlessness and night-time pacing. Some owners describe a dog that cannot settle, wanders the house at night, or seems mildly irritable. This is easily attributed to canine cognitive decline in an older dog, which is exactly why the whole picture matters more than any single sign.

What the changes look like from across the room

Searches for photographs of this condition are extremely common, and there is a reason: the later-stage appearance is distinctive. What you are looking for is a dog that looks heavier in the middle and thinner everywhere else.

The belly. The classic pot-bellied look is not simple weight gain and it is not gas. It is a combination of fat redistributed into the abdomen, abdominal wall muscles that have weakened and no longer hold the contents in, and a liver that enlarges under sustained cortisol. The outline sags downward and the dog looks slung low in the middle, while the waist disappears when viewed from above. Owners often describe it as bloating, and that word matters: this kind of swelling develops over weeks and months, is soft, and is not painful. True bloat, or gastric dilatation and volvulus, is sudden, the abdomen is hard and tender, the dog retches unproductively, paces and deteriorates quickly. That is a surgical emergency and needs a vet immediately, not an appointment next week.

The coat. Hair thins over the flanks, chest, belly and back, usually symmetrically on both sides, while the head and legs are often spared until later. The coat may dull, the undercoat may be lost, and hair clipped for a blood draw can be slow to regrow. Unlike allergic skin disease, this hair loss is typically not itchy, which is a useful distinction to mention to your vet.

The skin. Skin becomes thin and papery, sometimes thin enough that blood vessels show through the belly. Bruises appear easily, small wounds take longer to close, blackheads can develop along the underside, and patches of darker pigment may appear. A minority of dogs develop calcinosis cutis, where calcium is deposited into the skin as firm, gritty, raised plaques, often along the back or neck. These are uncomfortable and always warrant veterinary attention.

The muscle. Run your hands along the spine and over the hind legs. In an affected dog, the bony ridges of the spine and the top of the skull become easier to feel, and the thighs lose their bulk. The contrast between a full-looking abdomen and a bony topline is the single most telling visual feature.

If you are comparing your dog against pictures online, use photographs of your own dog instead. Take one from the side and one from above, in the same spot and the same light, once a month. Slow change is very hard to see day to day and obvious in a line of photos. No photograph diagnoses anything: a pot belly, panting and hair loss can be produced by several different diseases, and distinguishing them requires blood, urine and hormone testing arranged by your veterinarian.

How the picture changes as the condition progresses

There is no official staging system for this disease in the way there is for heart or kidney disease. Vets describe progression by how far the changes have gone and what complications have appeared. The grouping below is a practical way to orient yourself, not a formal classification, and results vary from dog to dog: some dogs stay in the earliest picture for a long time, while others move through it faster.

Phase	What you tend to see	Easy to miss or mistake for
Early	Slightly more drinking and urinating, a bigger appetite, occasional panting, a little less stamina. Body shape still looks normal.	Normal ageing, hot weather, a change in diet or routine
Established	Obvious thirst and night-time urination, a visibly sagging abdomen, symmetrical thinning of the coat, thinner skin, loss of muscle over the spine and hind legs, panting at rest, repeat skin or urinary infections	Hypothyroidism, early diabetes, arthritis, cognitive decline
Advanced	Marked muscle wasting with a pronounced pot belly, very thin or bruising skin, poor wound healing, possible calcinosis cutis, pronounced weakness, and secondary problems such as high blood pressure, protein loss through the kidneys, or diabetes developing alongside	Rarely mistaken at this point, but the complications need their own workup

Progression is usually measured in months rather than days. A sudden change of any kind, particularly breathing difficulty, collapse, severe lethargy or refusal to eat, is not the normal course of this disease and should be treated as urgent.

Conditions that can look like Cushing's

This is the reason a symptom list cannot stand in for a diagnosis. Several common conditions produce overlapping signs, and more than one can be present at the same time.

Condition	Shared signs	What often differs
Diabetes mellitus	Heavy thirst, heavy urination, big appetite	Weight loss despite eating well; sugar found in the urine
Chronic kidney disease	Thirst, urination, lethargy, muscle loss	Reduced appetite, nausea, weight loss rather than a growing abdomen
Hypothyroidism	Coat thinning, lethargy, weight change	Usually no increase in thirst; skin tends to thicken rather than thin
Long-term steroid medication	The full outward picture, including pot belly and coat loss	Tied to a prescribed drug; managed only by the prescribing vet
Liver disease	Enlarged abdomen, lethargy, appetite change	Vomiting, jaundice, or abnormal liver values with a different pattern

When to call your vet, and when it is an emergency

Book a non-urgent appointment if your dog's water intake has clearly risen, if the body shape is changing, if the coat is thinning symmetrically without itching, or if infections keep returning. Bring your photographs, and if you can, note roughly how much water is going down in a day. That single piece of information is genuinely useful to a vet.

Go straight to emergency care for a hard, distended, painful abdomen with unproductive retching, laboured or noisy breathing, collapse or sudden hind-limb weakness, repeated vomiting, inability to pass urine, or a dog that will not eat or drink at all. Those signs are not the slow drift this condition causes, and they need to be assessed the same day.

Key Takeaways

• The core symptoms are increased thirst and urination, a bigger appetite, panting at rest, a pot-bellied abdomen, symmetrical non-itchy hair loss, thin skin and muscle wasting.
• The signature look is a dog that is full in the middle and bony along the spine and hind legs.
• A swollen belly that develops slowly and is soft is different from true bloat, which is sudden, hard, painful and an emergency.
• There is no formal staging system; vets describe progression by the extent of change and by which complications have appeared.
• Diabetes, kidney disease, thyroid disease, liver disease and long-term steroid medication can all look similar, so testing is what separates them.
• Never stop or adjust a prescribed steroid without veterinary guidance.

If you recognise your dog in this article, the next step is a veterinary appointment, not a search for a home remedy. Your veterinarian owns the diagnosis and the treatment plan here: deciding which tests are appropriate, interpreting them in the context of your dog's age and other conditions, and monitoring over time. Diet, weight management, gentle consistent exercise and good skin care all matter, but they work alongside that plan rather than in place of it. Bring your questions, bring your photos, and ask what you should be watching for between visits.

For a wider rundown of the signs that mean same-day veterinary attention rather than a scheduled appointment, see Dog Emergency Signs.