Cushing in dogs: symptoms, diagnosis and treatment

by Nicolas Bartholomeeusen on Jun 14 2026· 6 min read

Key takeaways

Watch for increased thirst, urination, appetite, hair loss and a swollen abdomen, since these are the most common signs and often get mistaken for normal ageing.
Diagnosis takes more than one test: urine analysis plus blood tests like ACTH stimulation or LDDST, sometimes paired with ultrasound or imaging.
Most cases trace back to a pituitary tumour rather than the adrenal glands, and that distinction determines whether lifelong medication or surgery makes more sense.
Trilostane is the standard treatment and needs regular blood tests to dose safely, with dogs on medication often living a good quality of life for two to four years after diagnosis.

Cushing's disease in dogs, also known as hyperadrenocorticism, is a hormonal disorder where the body produces too much cortisol. Left unchecked, it can bring on skin problems, muscle weakness, excessive thirst and urination, and a distended abdomen. The condition tends to be chronic and progresses slowly, which is exactly why it's so often mistaken for normal ageing. So what symptoms should you actually watch for? How does a vet confirm the diagnosis? And what does treatment look like in practice? Here's what the evidence says.

What is Cushing's disease in dogs?

Cushing's disease happens when the adrenal glands produce too much cortisol. This stress hormone regulates metabolism, blood pressure and immune function among other things, but sustained excess causes real damage. In most dogs, the underlying driver is a pituitary tumour, roughly 80 to 85% of cases, with the remaining 15 to 20% caused by a tumour in the adrenal gland itself [1].

Which dogs are more prone to Cushing's disease?

Poodles, Dachshunds, Beagles, terriers (Border, Yorkshire and Jack Russell among them) and Boxers are commonly flagged as higher-risk breeds [1]. That said, a 2016 study of over 200,000 UK dogs found breed, bodyweight and age all played a measurable role, and identified the Bichon Frise as carrying the highest relative odds in that particular population [2], a reminder that breed-risk data can shift depending on which population gets studied. Age matters too: Cushing's mainly shows up in dogs over six.

What are the symptoms of Cushing's in dogs?

The most common signs are:

Increased water intake and urination
A noticeably bigger appetite
Thinning skin and hair loss, particularly on the flanks and tail
A swollen, pot-bellied abdomen from fat redistribution
Reduced muscle strength and stamina
Excessive panting, even at rest

What lesser-known symptoms might a dog with Cushing's disease have?

Beyond the classic list, some dogs develop:

Skin changes such as blackheads, dark pigmentation or thickened skin
Diabetes mellitus, driven by chronically high cortisol
Urinary tract infections, since cortisol suppresses immune function
Slow wound healing
Absence of heat cycles in unspayed females

These symptoms tend to creep in gradually over the course of a year, which is exactly why early signs get written off as "just getting older."

Good to know

Cushing's disease rarely travels alone. A review of complications found that untreated, sustained excess cortisol is linked to hypertension, glucose intolerance, pancreatitis and thromboembolism, on top of the muscle wasting and infections most owners already expect [5]. That's the real argument for catching it early rather than waiting to see if symptoms settle down.

How is Cushing's disease diagnosed in dogs?

Diagnosis isn't a single test. It typically takes a few, layered together, per the 2012 ACVIM consensus guidelines on diagnosing spontaneous canine hyperadrenocorticism [1].

Which tests are used to detect Cushing's disease in dogs?

Urine analysis: a cortisol-to-creatinine ratio in morning urine gives an initial indication. Repeating it over three days improves reliability.
Blood tests: the ACTH stimulation test checks how the adrenal glands respond to ACTH, the hormone that drives cortisol production. The low-dose dexamethasone suppression test (LDDST) checks whether the body can suppress cortisol under dexamethasone, and helps distinguish pituitary-dependent from adrenal-dependent disease [1].
Imaging: ultrasound can reveal enlarged or asymmetrical adrenal glands, a sign of a possible tumour. MRI or CT gets used when a pituitary tumour is suspected specifically.

Getting the diagnosis right matters, because treatment depends entirely on which type you're dealing with.

What are the treatment options for Cushing's in dogs?

Treatment depends on the cause and how advanced things are.

Which medication helps with Cushing's in dogs?

Trilostane (sold as Vetoryl®) is the standard medical treatment. It inhibits cortisol production in the adrenal glands and is given for life, alongside regular monitoring, typically ACTH stimulation testing, to keep the dose accurate [3][4]. Getting the dose wrong in either direction causes problems, so this isn't a "set it and forget it" medication.

Is surgery an option for Cushing's disease?

Yes, especially when an adrenal tumour is the cause. Surgical removal can be curative in that case. A large pituitary tumour can technically be removed too, but the procedure is complex and rarely performed in general practice.

What role does nutrition play in dogs with Cushing's disease?

A modified diet supports treatment rather than replacing it:

Lower fat, to ease the load on the pancreas
Fewer carbohydrates and sugars, to reduce diabetes risk
High-quality protein, to help maintain muscle
Omega-3 fatty acids, to support skin and coat health

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What is the prognosis for a dog with Cushing's?

Dogs on medication typically live 2 to 4 years after diagnosis with a good quality of life.
Adrenal tumours, if removed with no metastasis, can mean a normal life expectancy.
Left untreated, dogs often develop muscle wasting, infections and diabetes, which shorten life expectancy considerably [5].

Frequently asked questions about Cushing's disease in dogs

Can Cushing's disease be cured?

Only if an adrenal tumour is successfully removed. With a pituitary tumour, medication is usually the only realistic way to keep symptoms under control long-term.

How quickly does a dog improve after starting treatment?

Excessive drinking and appetite often ease within 2 to 4 weeks of starting trilostane. Hair loss and skin problems take longer, usually a few months.

Is Cushing's disease contagious to other pets?

No. It's not contagious, and it only affects the individual dog.

Are there side effects from Cushing's medication?

Yes. Trilostane can cause lethargy, vomiting, diarrhoea, weakness or appetite loss. Regular blood tests catch overdosing before it becomes dangerous.

What happens if Cushing's remains untreated?

Severe muscle wasting, immune problems, high blood pressure, diabetes, and eventually kidney or heart failure [5].

Conclusion

Cushing's disease in dogs is a chronic hormonal disorder that shows up most often in older dogs and certain breeds. Catching the early signs, excessive thirst, hair loss, a swelling abdomen, matters, because timely diagnosis changes the outlook considerably. Trilostane remains the most common treatment path, with surgery reserved mostly for adrenal tumours. A tailored diet and consistent check-ups round out the picture and help protect quality of life over the years that follow.

If your dog is showing any of these symptoms, a vet visit is the right next step, not a wait-and-see approach.

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A hypoallergenic, plant-based omega-3 can help with the skin and coat side of chronic conditions like Cushing's.

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References

[1] Behrend EN, Kooistra HS, Nelson R, Reusch CE, Scott-Moncrieff JC. Diagnosis of spontaneous canine hyperadrenocorticism: 2012 ACVIM consensus statement (small animal). J Vet Intern Med. 2013;27(6):1292-1304. doi:10.1111/jvim.12192
[2] O'Neill DG, Scudder C, Faire JM, et al. Epidemiology of hyperadrenocorticism among 210,824 dogs attending primary-care veterinary practices in the UK from 2009 to 2014. J Small Anim Pract. 2016;57(7):365-373. doi:10.1111/jsap.12523
[3] Golinelli S, de Marco V, Leal RO, et al. Comparison of methods to monitor dogs with hypercortisolism treated with trilostane. J Vet Intern Med. 2021;35(6):2616-2627. doi:10.1111/jvim.16269
[4] Arenas Bermejo C, Pérez Alenza D, García San José P, et al. Laboratory assessment of trilostane treatment in dogs with pituitary-dependent hyperadrenocorticism. J Vet Intern Med. 2020;34(4):1413-1422. doi:10.1111/jvim.15830
[5] Nichols R. Complications and concurrent disease associated with canine hyperadrenocorticism. Vet Clin North Am Small Anim Pract. 1997;27(2):309-320. doi:10.1016/s0195-5616(97)50034-9

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