Cushing's Disease in Dogs and Cats: Symptoms, Diagnosis, and Treatment Guide

When your once energetic senior pet starts drinking bowls of water, asking to go outside constantly, gaining weight despite no diet change, or losing fur in patches, it is cause for pause and sometimes concern. One possible cause is Cushing’s disease (also known as Cushing’s syndrome and hyperadrenocorticism in animals), a hormonal disorder caused by too much cortisol production in the pet dog or cat's body. Cushing's syndrome is particularly important to diagnose and treat in dogs, as it can significantly impact their quality of life (Feldman and Nelson ,1994).

Cushing's disease is also a significant health problem in humans, but this article focuses on pets.

In this comprehensive guide, we’ll break down everything pet owners need to know about Cushing’s disease in dogs and cats, focusing on animal health. Understanding Cushing's disease helps address broader health problems in pets. We’ll cover causes, symptoms, diagnosis, treatment options, and long term management for animals, especially dogs and cats.

What Is Cushing’s Syndrome or Disease?

Cushing's Syndrome, is a disease in which the body produces excess cortisol over a prolonged period of time.

Cortisol is a stress hormone made by the adrenal glands. The body makes cortisol through a hormone system involving the hypothalamus, pituitary gland, and adrenal glands, known as the hypothalamic-pituitary-adrenal (HPA) axis.

In normal amounts, it helps regulate the metabolism, blood sugar, immune response, blood pressure and inflammation. When cortisol levels remain high for months or years, it begins to damage the body.

Another name you may hear is Hyperadrenocorticism, which literally means “overactive adrenal glands.”

A Simple Explanation of How the Hormone System Works

To understand Cushing’s disease, it helps to know how cortisol production is controlled. First, the brain releases a hormone called adrenocorticotropic hormone (ACTH). ACTH signals the adrenal glands (located near the kidneys). The adrenal glands produce cortisol. Once enough cortisol is present, the brain tells the body to slow down production.

In rare cases, tumors outside the pituitary gland can produce ACTH, leading to a condition called ectopic ACTH syndrome, which also results in excessive cortisol production.

In Cushing’s disease, this regulation system breaks down and cortisol keeps being produced even when the body doesn’t need it.

Underlying Cause andTypes of Cushing’s Disease in Dogs

There are three main types in dogs: pituitary dependent, adrenal dependent, and iatrogenic. In many cases, Cushing’s disease in dogs is pituitary dependent, which accounts for 80–85% of all cases. Pituitary dependent Cushing's disease is most often caused by pituitary tumors, which require specialized diagnosis and treatment.

Pituitary-Dependent Cushing’s Disease

This accounts for about 80–85% of cases in dogs.

A small tumor forms in the pituitary gland (in the brain). Pituitary tumors are typically diagnosed with imaging techniques and may require specialized treatment, including medication or surgery, under veterinary supervision. The tumor produces too much ACTH, which overstimulates the adrenal glands. It is usually a benign (non-cancerous) growth that progresses slowly. It is the form most common in senior dogs.

Adrenal Gland Dependent Cushing’s Disease

In this type, a tumor forms directly on one adrenal gland. It may be benign or malignant and often requires surgery.

Iatrogenic Cushing’s Disease

This occurs when a dog receives long-term steroid medication (like prednisone). Steroids mimic cortisol in the body. Prolonged use can cause Cushing-like symptoms. The good news: this type can often be reversed with careful medication tapering under veterinary supervision (Schaer and Ginn, 1999).

Cushing’s Disease in Cats

Cushing’s disease is much rarer in cats than in dogs, but it does occur.

In cats most cases are pituitary-dependent. They are often linked with preexisting diabetes. The skin becomes extremely fragile and thin (a classic sign in cats). Because it is uncommon, diagnosis in cats can be more challenging and often requires advanced testing.

Common Symptoms of Cushing’s Disease in Dogs

Cushing’s disease typically develops slowly, and early signs are often mistaken for “normal aging.” The condition occurs when certain tumors, such as pituitary or adrenal tumors, cause the body to produce more cortisol than normal. This excess cortisol leads to a range of symptoms and can drastically change your body.

Increased Thirst & Urination

Things like drinking excessive water and frequent accidents indoors or asking to go outside more often are common indicators of Cushing's.

Increased Appetite

Dog's will show increased begging for food, stealing food and or weight gain.

Pot-Bellied Appearance

One of the classic signs. The abdomen appears round or swollen due to:

• Muscle weakening

• Fat redistribution

• Enlarged liver

Hair Loss (Symmetrical Alopecia)

Hair thinning on both sides of you dog and bald patches accompanied with slow hair regrowth are all common signs as well.

Thin Skin

Thin skin that bruises easily and skin tears more easily is also common.

Muscle Weakness

Muscle weakness can be identified with signs like difficulty climbing stairs, reluctance to jump or even back legs appearing weak.

Panting

You will also notice excessive panting, even at rest.

Recurrent Infections

Skin infections and urinary tract infections are most common and reocurring.

If you notice several of these together, it’s time to consult your veterinarian.

Symptoms of Cushing’s Disease in Cats

Cats show some similar signs but also unique ones:

• Increased thirst and urination

• Increased appetite (as always your cat's eating patterns should be monitored)

• Poor coat quality

• Severe thinning of skin (risk of injury)

• Muscle weakness

• Diabetes that is difficult to regulate

Thin, fragile skin is especially characteristic in cats with Cushing’s.

Dog Breeds at Higher Risk

While any dog can develop Cushing’s disease, certain breeds are more predisposed. Breeds like Poodles, Dachshunds, Boxers, Boston Terriers, Yorkshire Terriers and Beagles tend to have a higher incidence of the disease.

Most affected dogs are middle-aged to senior (typically 8+ years old).

How Is Cushing’s Disease Diagnosed?

Diagnosis isn’t based on symptoms alone. Many signs overlap with other conditions.

Veterinarians typically use:

Blood Tests

A complete blood count and blood chemistry will be run with your pet's blood sample. Your vet will look for elevated liver enzymes, high cholesterol and blood sugar changes.

Urinalysis

A urine sample is taken and evaluated. Diluted urine and signs of infection are common findings that can point to Cushing's.

ACTH Stimulation Test

Measures how the adrenal glands respond to stimulation by adrenocorticotropic hormone (ACTH). ACTH is a hormone produced in the pituitary gland that makes the adrenal glands produce cortisol. This test helps in diagnosing and differentiating types of Cushing's disease.

Low Dose Dexamethasone Suppression Test (LDDST)

Helps confirm Cushing’s disease and sometimes determine type. A small amount of dexamethasone, a steroid medication, is given by injection, and blood samples are taken over several hours to see how the dog’s body responds. In healthy dogs the medication tells the body to temporarily lower its cortisol levels, but in dogs with Cushing’s disease the cortisol often stays higher than normal.

Ultrasound

Used to check for adrenal tumors by visualizing the adrenal glands.

Diagnosis can take multiple visits and tests. It’s a process of confirming patterns rather than relying on a single result.

Treatment Options for Dogs

Treatment depends on the type and severity. While most cases are managed with medication, a cure is possible if the adrenal tumor can be completely removed. Treatments for Cushing syndrome can lower the body's cortisol levels and improve symptoms, and the sooner treatment starts, the better the chances for recovery (Pivonello et al., 2015). Cushing syndrome can be treated with medications that help manage cortisol levels, and surgical options may be available, especially if a tumor is present. Regular monitoring and follow-up with a healthcare provider are important during treatment for Cushing syndrome. Medications can be used to lower cortisol levels when surgery is not enough or not possible (Peterson, 2001).

Medications

Vetoryl (trilostane) is the only drug approved by the FDA to treat both pituitary and adrenal dependent Cushing's disease in dogs. Anipryl is another FDA approved drug, but it is only used for certain cases caused by a pituitary tumor. These medications are important options for managing the condition and controlling cortisol levels, especially when surgery is not possible. Regular monitoring and follow-up with a healthcare provider are important during treatment for Cushing's disease.

Trilostane reduces cortisol production, is used as a lifelong treatment, needs regular monitoring blood tests and has possible side effects. These include poor appetite, vomiting, diarrhea, or more serious complications, so close monitoring and prompt reporting to your veterinarian are important.

Some medications used to treat Cushing's disease in dogs are actually human drugs, but these should only be given to animals under strict veterinary supervision.

Another medication sometimes used is mitotane (less common today).

Surgery

If an adrenal tumor is present, surgical removal may be recommended. In some cases, surgical removal of the adrenal tumor can cure Cushing's disease (Hara et al., 2010).

Surgery is the first line treatment for Cushing's disease, especially when caused by a pituitary tumor.

Bilateral adrenalectomy (removal of both adrenal glands) is considered a last resort to stop cortisol production and requires lifelong hormone replacement therapy.

Radiation therapy may be used if the tumor cannot be fully removed or if it recurs after surgery. An advanced method, called stereotactic radiosurgery, that delivers a single but highly focused dose of radiation directly to the tumor.

Adjusting Steroid Use

If caused by long-term steroid medication, your veterinarian will gradually reduce the dose.

Never stop steroids abruptly as it can be life-threatening.

Treatment Options for Cats

Treatment in cats can be more complex.

Options include trilostane medication, surgical removal of adrenal tumor and managing concurrent diabetes (Cook and Evans, 2021). Prognosis varies depending on severity and complications.

What Happens If Cushing’s Disease Is Left Untreated?

Untreated Cushing’s can lead to a range of serious health problems affecting multiple organ systems, including:

• High blood pressure

• Blood clots

• Diabetes

• Severe infections

• Muscle wasting

• Reduced quality of life

If left untreated, Cushing’s disease can ultimately lead to death. The condition significantly impacts overall health, making individuals more vulnerable to other diseases and increasing the risk of serious complications.

While it progresses slowly, it does shorten lifespan if unmanaged.

Life Expectancy

With proper treatment, many dogs live 2–4+ years after diagnosis, sometimes longer.

Factors influencing prognosis:

• Type (pituitary vs adrenal)

• Presence of co existing cancer

• Early detection

• Owner compliance with medication and monitoring

Cats have more variable outcomes due to complexity and diabetes involvement.

Managing a Pet with Cushing’s at Home

Cushing’s disease is usually manageable but requires commitment. Managing Cushing's disease can also affect the mental health of both pets and their owners, so seeking support and understanding the psychological impact is important.

Regular Monitoring

Prepare for taking your pet in for blood tests every 3–6 months and watch for any symptom return.

Track Symptoms

Keep notes on water intake, appetite, urination frequency and energy levels.

Support Mobility

Because muscle weakness is common think of making your pet comfortable by providing ramps, using orthopedic beds and making changes to avoid slippery floors.

Prevent Infections

Monitor skin closely and schedule routine vet checks.

Diet & Lifestyle Considerations

While no specific “Cushing’s diet” exists, general guidelines include:

• Moderate fat levels

• High-quality protein

• Controlled calorie intake

• Avoid excessive treats

Always consult your veterinarian before making dietary changes.

Emotional Impact on Pet Owners

Many owners feel guilty about not noticing signs of illness sooner. It's important to keep in mind that sometimes when you see your pet everyday, small changes aren't noticeable. Cushing’s disease develops gradually and is not caused by neglect. Early detection can be difficult because signs resemble aging.

Anxiety about medication and stress about costs can also take an emotional toll on an owner. Chronic disease diagnoses will need a budget as this is something you will have to deal with for the rest of your pet's life.

Family members can play an important role in supporting both the pet and the owner during treatment and management.

The good news is, with proper care, many pets continue to enjoy happy, comfortable lives.

Frequently Asked Questions

Is Cushing’s disease painful?

It’s not directly painful, but complications like infections and muscle weakness can cause discomfort. Pain, while not a primary symptom of Cushing's disease, can occur due to these complications and may negatively affect the animal's quality of life.

Can Cushing’s disease be cured?

If it is pituitary dependent, the disease is usually managed, not cured.

If it is adrenaldependent, surgical removal of the adrenal tumor can sometimes result in a cure. Keep in mind though most cases are managed with medication.

When it's atrogenic, the disease is often reversible.

Is Cushing’s contagious?

No. It is a hormonal disorder, not an infectious disease.

When Should You See a Vet?

Schedule a veterinary visit if your senior pet shows:

• Sudden increase in thirst

• Frequent urination

• Pot-bellied appearance

• Hair loss

• Excessive panting

• Recurrent infections

Cushing's disease does not spread between animals, but if left untreated, its effects can spread throughout the body and impact multiple organ systems. Early diagnosis improves outcomes significantly. If you notice any of these symptoms, consult your healthcare provider promptly to ensure proper management and treatment.

Resposible Care in Pets with Cushing's

Cushing’s disease in dogs, and more rarely in cats , is a common endocrine disorder in senior pets. It is an example of an endocrine disorder where advances in science have significantly improved both diagnosis and treatment. While it can sound overwhelming at first, it is often manageable with medication, monitoring, and supportive care.

If your pet has recently been diagnosed, remember:

• Many pets live years with proper treatment.

• Routine monitoring makes a huge difference.

• Quality of life is the primary goal.

Aging pets deserve comfort, dignity, and proactive care. Responsible cat and dog ownership makes understanding conditions like Cushing’s disease, an important step in giving them quality care. Your ability to identify something is wrong with your pet's physical health and seeking out medical treatment early, can make all the difference in prognosis and quality of life.

References

Cook, A. K., & Evans, J. B. (2021). Feline comorbidities: recognition, diagnosis and management of the cushingoid diabetic. Journal of feline medicine and surgery, 23(1), 4-16.

Feldman, E. C., & Nelson, R. W. (1994). Comparative aspects of Cushing’s syndrome in dogs and cats. Endocrinology and metabolism clinics of North America, 23(3), 671-691.

Hara, Y., Teshima, T., Taoda, T., Ishino, H., Nezu, Y., Harada, Y., ... & Tagawa, M. (2010). Efficacy of transsphenoidal surgery on endocrinological status and serum chemistry parameters in dogs with Cushing's disease. Journal of Veterinary Medical Science, 72(4), 397-404.

Peterson, M. E. (2001). Medical treatment of canine pituitary-dependent hyperadrenocorticism (Cushing's disease). Veterinary Clinics: Small Animal Practice, 31(5), 1005-1014.

Pivonello, R., De Leo, M., Cozzolino, A., & Colao, A. (2015). The treatment of Cushing's disease. Endocrine reviews, 36(4), 385-486.

Schaer, M., & Ginn, P. E. (1999). Iatrogenic Cushing's syndrome and steroid hepatopathy in a cat. Journal of the American Animal Hospital Association, 35(1), 48-51.