Cushing's Disease in Dogs: Signs, Testing and Treatment

What Cushing's disease is

Cortisol is a stress hormone made by the adrenal glands, under instructions from the pituitary gland at the base of the brain. In Cushing's disease, or hyperadrenocorticism, there is too much of it for too long. VCA reports that 85 to 90 percent of cases are pituitary dependent, caused by a usually small, benign pituitary tumor that over-stimulates both adrenal glands. Most of the rest are caused by a tumor in one adrenal gland, which may be benign or malignant.

A third form, called iatrogenic Cushing's, is caused by long-term or high use of steroid medicines prescribed for another condition. The AKC notes that Cushing's is diagnosed in under 1 percent of dogs, mostly in dogs under about 44 pounds, and that Poodles, Dachshunds, Boston Terriers, Boxers and Beagles are among the breeds predisposed. It is most often recognized in middle-aged and senior dogs.

Signs of Cushing's disease in dogs

The most common early signs are drinking much more water, peeing more often or having accidents indoors, and a large appetite, sometimes with food stealing. Over months, many dogs develop a pot-bellied look, muscle loss over the back and legs, panting at rest, low energy, and a thin, dull coat with hair loss on the flanks, neck and around the rear. The skin may become thin, with visible blood vessels, dark patches or hard white spots, and wounds may heal slowly.

Repeated skin and bladder infections are common because excess cortisol suppresses the immune system. The AKC points out that signs often develop over a year or more, so owners may see them as normal aging. Diabetes, kidney disease, liver disease and, in unspayed females, a uterine infection can all cause increased thirst too, which is why testing matters.

When to call your vet today

Book a visit within a few days if your dog is drinking noticeably more, needs to go out more often or overnight, has started having accidents, is unusually hungry, or has developed a pot belly, hair loss or thin skin. Measuring how much water your dog drinks over 24 hours and bringing a fresh urine sample makes the first visit more useful.

Call sooner if your dog also has a poor appetite, vomiting, weight loss or lethargy, since those fit other illnesses better than Cushing's. For a dog already on treatment, call your vet promptly if it stops eating, vomits, has diarrhea or seems weak, because these can be signs that the dose needs adjusting.

When it's an emergency

Cushing's itself develops slowly and is rarely an emergency, but dogs with it are at higher risk of some serious problems. Go to your vet or the nearest emergency vet immediately if your dog has sudden difficulty breathing, collapses, has a seizure, starts circling or acting confused, or suddenly cannot walk.

For a dog being treated for Cushing's, sudden weakness, collapse, repeated vomiting or diarrhea can mean cortisol has fallen too low. Call your vet or an emergency vet right away and tell them about the medicine, as this needs prompt assessment.

What you can safely do at home

Do not limit water for a dog that is drinking a lot. Restricting water can cause dangerous dehydration whatever the cause. Instead, offer plenty of fresh water, give more frequent toilet breaks, and keep a simple record of water intake, appetite, weight and any new skin changes for your vet.

Do not stop any steroid medicine suddenly if your dog is taking one for another condition, even if you suspect it is causing signs; steroids must be reduced gradually under your vet's guidance. Avoid supplements marketed for adrenal health, which have not been shown to treat Cushing's and can interfere with testing.

Frequent urination can mean accidents, so washable pee pads by the door can help while treatment is adjusted.

What the vet will likely check

Diagnosis starts with blood work and a urine test. Many dogs with Cushing's have a raised liver enzyme called ALP, dilute urine, and sometimes protein in the urine or a urine infection. To confirm it, your vet will use a hormone test such as the low-dose dexamethasone suppression test or the ACTH stimulation test, which measure how the body's cortisol responds to an injection. An abdominal ultrasound helps tell pituitary from adrenal disease and checks the liver.

Pituitary-dependent Cushing's is usually managed with daily medicine that reduces cortisol production, given for life, with regular blood tests to fine-tune the dose; the AKC notes rechecks often every 3 to 6 months. Adrenal tumors are often treated with surgery, and a benign one that is fully removed can be cured. Iatrogenic Cushing's is managed by gradually reducing the steroid that caused it.

Living with a dog with Cushing's

Cushing's cannot be prevented, except for the iatrogenic form, where using steroids only as your vet directs and at the lowest effective level reduces the risk. What matters most is consistent treatment: give medicine at the same time each day with food if your vet advises, keep every recheck, and never run out.

Most dogs on well-controlled treatment drink and pee less within weeks, and their coat and energy improve over months. Watch for signs that treatment is working too well, such as a poor appetite, vomiting, diarrhea or weakness, and call your vet if you see them.

This page is general information, not veterinary advice, and it cannot replace an examination by the vet who knows your pet.