Untreated Cushing’s Disease in Dogs: What Happens & Scary Risks

Untreated Cushing’s Disease in Dogs: What Happens?

Untreated Cushing’s disease in dogs is a progressive endocrine disorder that worsens over time without intervention. It occurs when a dog produces excessive cortisol, a hormone that affects metabolism, immunity, and nearly every organ system.

The medical term for this condition is Cushing’s syndrome, and while it can often be managed with treatment, leaving it unmanaged leads to serious and sometimes life-threatening complications.

Table of Contents

What Is Cushing’s Disease in Dogs?

Cushing’s disease develops when the body produces too much cortisol due to:

Pituitary gland tumours (most common cause)
Adrenal gland tumours
Long-term steroid medication use

Cortisol plays an important role in the body, but when levels remain high for prolonged periods, it begins to break down tissues, suppress immunity, and disrupt normal metabolism.

Early Signs of Untreated Cushing’s Disease in Dogs

One of the challenges with untreated Cushing’s disease in dogs is that early signs are often subtle and mistaken for ageing.

Common early symptoms include:

Increased thirst (polydipsia)
Increased urination (polyuria)
Increased appetite
Panting at rest
Reduced energy levels
Mild weight gain
Pot-bellied appearance
Hair thinning or coat changes

Because these signs develop gradually, many dogs go undiagnosed in the early stages.

Untreated Cushing’s Disease in Dogs: What Happens If Left Untreated?

When untreated Cushing’s disease in dogs progresses, it begins to affect multiple body systems. The condition does not stabilise on its own and will continue to worsen.

Muscle Wasting and Weakness

High cortisol levels break down muscle protein over time, leading to:

Loss of muscle mass (especially along the spine)
Weakness and fatigue
Reduced ability to exercise
Difficulty climbing stairs or jumping

Dogs often become noticeably weaker as the disease progresses.

Skin and Coat Deterioration

One of the most visible effects of untreated Cushing’s disease in dogs is skin damage.

This includes:

Severe hair loss (alopecia)
Thin, fragile skin
Slow healing wounds
Frequent skin infections
Blackheads and skin changes

These issues occur because cortisol suppresses immune and skin repair functions.

Recurrent Infections

Dogs with untreated Cushing’s disease in dogs are highly prone to infection due to immune suppression.

Common infections include:

Urinary tract infections
Skin infections (pyoderma)
Ear infections

Recurring infections are often one of the earliest clinical red flags.

Urinary Problems and Excessive Thirst

Cortisol disrupts normal kidney function, leading to:

Excessive drinking
Frequent urination
Urinary accidents indoors
Increased risk of bladder infections

Over time, this can place strain on the urinary system and kidneys.

High Blood Pressure and Organ Damage

One of the more serious complications of untreated Cushing’s disease in dogs is hypertension (high blood pressure).

This increases the risk of:

Kidney damage
Heart disease
Sudden blindness (retinal damage)
Neurological complications

Diabetes Mellitus Risk

Cortisol interferes with insulin regulation, which can lead to:

Insulin resistance
Development of diabetes mellitus
Weight loss despite increased appetite
Increased thirst and urination

Dogs with both conditions require complex medical management.

Behavioural Changes

Hormonal imbalance may also affect behaviour, causing:

Restlessness or pacing
Anxiety-like behaviour
Sleep disturbances
Reduced interaction or dullness

In advanced cases involving pituitary tumours, neurological signs may appear.

Worsening Pot-Bellied Appearance

As untreated Cushing’s disease in dogs progresses:

Abdominal fat redistributes
Muscle weakness increases
Liver enlargement may occur

This leads to a more pronounced “pot belly” appearance.

Liver Enlargement and Dysfunction

The liver is commonly affected in untreated cases.

Effects include:

Enlarged liver (hepatomegaly)
Elevated liver enzymes
Reduced liver efficiency
Lethargy and digestive changes

Severe Complications in Advanced Cases

If left untreated long-term, complications can become severe:

Life-threatening infections (sepsis)
Blood clots
Organ failure
Collapse episodes

Although progression is gradual, the cumulative damage becomes significant.

Life Expectancy With Untreated Cushing’s Disease in Dogs

Dogs with untreated Cushing’s disease in dogs typically experience:

Progressive decline in quality of life
Increased infection frequency
Reduced lifespan compared to treated dogs

More importantly, many dogs live with ongoing discomfort before severe complications occur.

Diagnosis and Why Early Treatment Matters

Early diagnosis allows veterinarians to control cortisol levels and prevent complications.

Common diagnostic tests include:

ACTH stimulation test
Low-dose dexamethasone suppression test
Blood tests and urinalysis
Ultrasound imaging

Treatment Options for Cushing’s Disease

While this article focuses on untreated disease, treatment is available and often effective.

Options include:

Medication (e.g. trilostane)
Surgery for adrenal tumours
Adjusting steroid medications (iatrogenic cases)

With treatment, many dogs regain good quality of life.

Key Takeaway

Untreated Cushing’s disease in dogs is a progressive condition that affects nearly every organ system. Without treatment, dogs develop worsening skin disease, muscle loss, infections, and metabolic complications such as diabetes.

Early diagnosis and treatment are essential to improving both lifespan and quality of life.

If your dog is showing signs such as increased thirst, urination, or a pot-bellied appearance, veterinary assessment is strongly recommended.

Useful link: Cushing’s Disease in dogs – PDSA