Cushing’s Disease in Cats: Hyperadrenocorticism Symptoms and Treatment

Last updated: May 16, 2026

What Cushing’s Disease in Cats Actually Is

Cushing’s disease in cats, known clinically as hyperadrenocorticism, is a syndrome in which the body is exposed to too much cortisol over a long period of time. Cortisol is the body’s main stress hormone, produced by the adrenal glands that sit on top of the kidneys, and at normal levels it helps regulate metabolism, blood sugar, blood pressure, and the immune response. When cortisol stays elevated for months or years, the cat’s metabolism slowly unravels.

The condition is well known in dogs and is the cat-side counterpart to a much more common canine disease. It is genuinely rare in cats, and many feline veterinarians may diagnose only a handful of cases over a long career. That rarity is part of what makes it dangerous. Owners and even some general practitioners may not have it on their differential list, and cats with classic signs sometimes wait years for the right blood test to be ordered.

Iatrogenic vs Spontaneous: Two Very Different Stories

Feline Cushing’s syndrome comes in two main forms, and the difference matters because the treatment paths diverge. Iatrogenic Cushing’s is caused by long-term, high-dose steroid medication, usually prednisolone or dexamethasone given for chronic skin disease, asthma, or inflammatory bowel issues. The cat’s adrenal glands are not the problem; the medication itself is supplying the excess cortisol. The treatment is to taper the steroid carefully under veterinary supervision, never abruptly, because abrupt withdrawal can trigger an Addisonian crisis.

Spontaneous Cushing’s is the disease form most veterinary textbooks describe. About 80 percent of spontaneous feline cases are pituitary-dependent: a small benign tumor in the pituitary gland at the base of the brain pumps out adrenocorticotropic hormone (ACTH), which orders the adrenal glands to make too much cortisol. The remaining cases are adrenal-dependent, meaning a tumor on one of the adrenal glands themselves is producing cortisol autonomously.

Why Diabetes Is Almost Always Part of the Picture

One of the most distinctive features of feline Cushing’s is its overwhelming connection to diabetes. The vast majority of cats with spontaneous Cushing’s are also diabetic, and many of them have insulin-resistant diabetes that does not respond well to standard doses. If your cat is on insulin and the blood glucose simply will not come down despite escalating doses, your veterinarian will start asking whether something else, like Cushing’s or acromegaly, is driving the resistance.

This pairing is not a coincidence. Cortisol is a counter-regulatory hormone, meaning it actively works against insulin. Chronic high cortisol forces the pancreas to produce more and more insulin until the beta cells exhaust themselves, at which point overt diabetes appears. Treating the underlying Cushing’s often improves diabetic control dramatically and sometimes allows insulin to be reduced or even discontinued, though this should never be attempted without your vet’s blood-glucose curve in hand.

Symptoms You Might Notice at Home

Feline Cushing’s is sneaky. The signs creep in over months and are often dismissed as aging. Owners frequently describe their cat as just slowing down, looking a bit scruffy, or drinking more water than usual. The classic constellation includes:

• Increased thirst and urination, often with larger clumps in the litter box
• Increased appetite that does not translate to weight gain — sometimes weight loss
• A pot-bellied or pendulous abdomen from muscle wasting and fat redistribution
• Thin, fragile skin that tears easily, sometimes with a bruise-like appearance
• Hair coat changes: thinning, slow regrowth after grooming, or unkempt appearance
• Recurring urinary tract or skin infections that do not stay resolved
• Lethargy and reduced grooming
• Poor diabetic control despite high or escalating insulin doses

The skin fragility is unusually striking in feline Cushing’s. Some cats develop tears from gentle handling or grooming, and the skin can take an extraordinarily long time to heal. If you notice this combined with poorly controlled diabetes, ask your veterinarian specifically about Cushing’s testing.

How Veterinarians Confirm the Diagnosis

Diagnosing feline Cushing’s takes patience because no single test is perfect. Your veterinarian will start with the basics: a thorough history, physical exam, complete blood count, chemistry panel, urinalysis, and usually a urine cortisol-to-creatinine ratio as a screening tool. Routine bloodwork might reveal elevated liver enzymes, high cholesterol, and stress-pattern white blood cell changes.

If screening looks suspicious, the gold-standard confirmatory test is the low-dose dexamethasone suppression test (LDDS), which is run differently in cats than in dogs. The test measures whether the adrenal axis can be suppressed by a small dose of synthetic cortisol; in Cushing’s cats, it cannot. ACTH stimulation testing is sometimes used as well, but it is less sensitive in cats than in dogs.

Once the syndrome is confirmed, the next question is whether the source is pituitary or adrenal. Abdominal ultrasound to image the adrenal glands, and sometimes an MRI of the pituitary, are the imaging tools of choice. This level of workup almost always benefits from a board-certified ACVIM internal medicine specialist, and asking your primary vet for a referral is reasonable at this stage.

Treatment Options Your Vet Will Discuss

Treatment depends on the form of disease. For pituitary-dependent feline Cushing’s, the most commonly used medication is trilostane, an oral drug that reduces cortisol synthesis in the adrenal glands. Trilostane is prescribed off-label in cats based on small case series and clinical experience; dose is highly individualized and your vet will recheck blood and adjust based on response. Lifelong monitoring with periodic ACTH stimulation testing or pre-pill cortisol testing is standard.

For adrenal-dependent disease caused by a unilateral adrenal tumor, surgical removal (adrenalectomy) is potentially curative if the tumor has not invaded surrounding vessels. This is a technically demanding surgery that should be performed by a board-certified ACVS surgeon at a referral hospital. Pre- and post-operative medical management, often with trilostane, is part of the protocol. For pituitary-dependent disease, transsphenoidal hypophysectomy (surgical removal of the pituitary tumor) is offered at a small number of specialty centers and can be curative, though it requires lifelong hormone replacement afterward.

Radiation therapy of the pituitary is another option for pituitary-dependent cases, particularly if the tumor is large or causing neurological signs. Your veterinary oncologist or internal medicine specialist will help weigh the trade-offs, including cost, travel, and the cat’s overall quality of life.

The Cost and Logistics Reality

Feline Cushing’s is one of the more expensive feline endocrine diagnoses. Confirmatory testing alone typically runs into hundreds of dollars, abdominal ultrasound adds more, and pituitary MRI plus radiation or surgery is firmly in the thousands. Lifelong trilostane therapy with periodic monitoring rechecks adds an ongoing monthly cost. None of this is a reason to give up — many cats live well with the condition for years — but it is a reason to ask your vet for a written estimate, look into pet insurance before symptoms appear, and explore options like CareCredit or local rescue and breed-club assistance funds. The veterinary specialist cost breakdown guide can help frame what to expect.

Living With a Cushing’s Cat: What Daily Life Looks Like

With well-controlled Cushing’s, most cats live a comfortable life that looks much like any senior cat’s. You will be giving daily medication, watching water intake and litter-box output, and bringing your cat in for periodic blood rechecks. Many owners find the routine settles in within a few weeks, particularly if the cat is also diabetic and already accustomed to twice-daily insulin injections.

Watch carefully for signs of over-suppression of cortisol — vomiting, diarrhea, profound lethargy, or weakness can indicate that trilostane has pushed cortisol too low and the cat is heading toward an Addisonian crisis. This is a true emergency, and your vet should be called immediately or, after hours, an emergency clinic. Always keep written discharge instructions on the fridge.

How Cushing’s Cats Differ From Cushing’s Dogs

Comparing feline and canine Cushing’s helps owners and even general practitioners frame the diagnosis. The dog form is overwhelmingly more common, and dog-side resources are extensive. Reviewing the canine framing in our Cushing’s syndrome in dogs guide, alongside the practical signs in dog Cushing’s disease signs, can help you recognize the syndrome conceptually even though feline cases look different at the bedside. The atypical Cushing’s disease in dogs overview covers a sex-hormone-driven variant that has a feline counterpart still being studied.

Key contrasts: dogs more often have classic potbelly and skin changes; cats more often present with diabetes that will not control. Dogs respond reliably to trilostane at established doses; cats need individualized dosing. Skin fragility is dramatic in feline Cushing’s and milder in dogs. The diagnostic test interpretation also differs, which is why a feline-experienced internist matters.

Prognosis and What to Expect

Prognosis for feline Cushing’s varies. Cats with adrenal tumors that can be surgically removed can do very well. Cats with pituitary-dependent disease who tolerate trilostane and have manageable diabetes also often do well, sometimes for years. Cats with large pituitary tumors that have begun causing neurological signs face a more guarded outlook. Concurrent diseases — uncontrolled diabetes, kidney disease, or congestive heart failure — affect prognosis significantly. Your veterinarian will frame expectations based on your specific cat, and qualitative phrasing like guarded, fair, or good with treatment is honest.

Quality-of-life conversations are part of long-term care for any chronic disease. Most owners find that sticking to a careful schedule of insulin, trilostane, fresh water, and regular weigh-ins gives them clear data points to discuss with their vet. If you are also managing a newly adopted senior cat with diabetes, the insulin management for new pet adopters guide pairs naturally with this article.

Frequently Asked Questions

Is Cushing’s disease in cats curable?

Sometimes. Surgical removal of an isolated adrenal tumor can be curative in adrenal-dependent disease. Pituitary surgery is curative at the small number of centers that perform it. For most cats, however, treatment is lifelong management rather than cure, similar to managing diabetes.

Can iatrogenic Cushing’s be reversed if I stop my cat’s steroids?

Often yes, but only with a careful taper supervised by your vet. Stopping steroids abruptly can throw the cat into adrenal insufficiency. The taper may take weeks to months, and the underlying condition that prompted the steroids in the first place will need a new treatment plan.

How is feline Cushing’s different from acromegaly?

Both can cause insulin-resistant diabetes in cats, and both involve pituitary tumors, but acromegaly involves growth hormone, not cortisol. The classic acromegalic cat has a broad face, large paws, and ongoing weight gain. The classic Cushing’s cat has a thin, fragile coat and pot-belly with muscle wasting. Both diagnoses require specific testing.

Will my cat’s diabetes go away if Cushing’s is treated?

Sometimes diabetes goes into remission once the cortisol excess is corrected, but not always. Many cats stay diabetic but become much easier to control on lower insulin doses. Always work with your vet on glucose curves before changing insulin dose.

Should I see a specialist or stay with my regular vet?

For initial diagnosis and stabilization, your primary vet may handle everything. For confirmatory testing, imaging, surgical evaluation, and complex cases, a board-certified ACVIM internal medicine specialist is well worth the referral. Ask your primary vet about local options.