Signs of Cushing's Disease in Senior Dogs: A Complete Guide

What Is Cushing's Disease in Senior Dogs?

If your older dog has been drinking more water than usual, developing a pot-bellied appearance, or losing hair in unusual patches, you may have already typed "signs of Cushing's disease in senior dogs" into a search bar — and you're right to investigate. Cushing's disease (medically known as hyperadrenocorticism) is one of the most frequently diagnosed hormonal disorders in middle-aged and senior dogs, and it's notoriously tricky to spot because so many of its symptoms look like plain old aging.

Understanding what Cushing's is, why it happens, and what the red flags look like can make a real difference in how quickly your dog gets relief. Early recognition gives your veterinarian more treatment options and gives your dog a better shot at a comfortable life.

Important: This guide is for educational purposes only. If you suspect your dog has Cushing's disease, please schedule an appointment with a licensed veterinarian. Only a vet can run the tests needed to confirm a diagnosis and recommend a safe treatment plan.

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What Causes Cushing's Disease?

📝 Editor's note: The aging comparison always comes up in these situations — and honestly, it makes so much sense. These symptoms are really hard to catch, but getting the right diagnosis makes such a difference in your pet's quality of life.

Cushing's disease occurs when a dog's body produces too much cortisol — often called the "stress hormone." Cortisol has a lot of important jobs: it regulates metabolism, manages inflammation, and helps the body respond to stress. But chronically elevated cortisol levels wreak havoc on nearly every organ system.

There are three main causes:

Pituitary-Dependent Cushing's (PDH)

This is by far the most common form, accounting for roughly 80–85% of cases. A small, usually benign tumor on the pituitary gland (a pea-sized gland at the base of the brain) causes it to over-signal the adrenal glands, which then pump out excess cortisol. Most dogs with this form have very small tumors that never cause neurological problems, though a small percentage develop large tumors that can affect the brain.

Adrenal-Dependent Cushing's

In about 15–20% of cases, a tumor grows directly on one of the adrenal glands (located near the kidneys). These tumors can be benign or malignant. Unlike pituitary tumors, adrenal tumors are sometimes surgically removable, which can potentially cure the disease entirely.

Iatrogenic Cushing's

This form is caused by long-term use of corticosteroid medications (like prednisone) given for other conditions. Once the underlying medication is tapered and stopped under veterinary supervision, this form typically resolves. It's important never to stop a corticosteroid suddenly without your vet's guidance.

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Which Dogs Are Most at Risk?

Cushing's disease is almost exclusively a condition of middle-aged to senior dogs, typically 6 years and older, with the average age of diagnosis being around 10–11 years. Certain breeds are significantly more predisposed:

• Poodles (all sizes, but especially Miniature and Standard)
• Dachshunds
• Beagles
• Boston Terriers
• Boxers
• Yorkshire Terriers
• Labrador Retrievers
• German Shepherds (more likely to develop the adrenal form)

Female dogs may be slightly more likely to develop adrenal tumors than males, but pituitary-dependent Cushing's affects both sexes fairly equally. Small-to-medium breeds seem to be disproportionately represented overall.

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The 10 Most Common Signs of Cushing's Disease in Senior Dogs

Because symptoms develop gradually over months or even years, many owners initially chalk them up to "just getting older." Here are the signs that should put Cushing's on your radar — especially if your dog has several of them at once.

1. Excessive Thirst and Urination (PU/PD)

One of the earliest and most consistent signs is polydipsia (drinking far more water than normal) paired with polyuria (urinating much more frequently). You might notice your dog asking to go outside more often, having accidents in the house for the first time, or emptying the water bowl several times a day. In senior dogs, this combination almost always warrants a vet visit, as it can also signal kidney disease or diabetes.

2. Increased Appetite (Polyphagia)

Excess cortisol directly stimulates appetite. Dogs with Cushing's are often ravenously hungry — counter-surfing, begging relentlessly, or appearing obsessed with food in a way that seems out of character. Owners sometimes attribute this to a "new lease on life," but it's actually a hormonal symptom.

3. Pot-Bellied Appearance (Abdominal Distension)

High cortisol causes fat redistribution (especially to the abdomen) and weakens the abdominal muscles and ligaments. The result is a distinctively pendulous, pot-bellied belly — even in dogs that haven't gained significant overall weight. The liver often enlarges (hepatomegaly) at the same time, further pushing the belly outward.

4. Hair Loss (Alopecia) and Poor Coat Quality

Many dogs with Cushing's develop symmetrical hair loss, most often on the flanks, belly, and the base of the tail — while the head and legs are usually spared. The remaining coat may look dull, dry, or thin. Some dogs stop shedding normally and develop a "fluffy" puppy-like coat texture as new guard hairs fail to grow in properly.

5. Thin or Fragile Skin

Cortisol breaks down proteins in skin tissue, leaving it thinner and more fragile than normal. Affected dogs may bruise easily, develop visible blood vessels through the skin, or get small white calcium deposits called calcinosis cutis — hard, chalky plaques most commonly found on the back and groin. Skin infections (both bacterial and fungal) are also more frequent because excess cortisol suppresses the immune system.

6. Muscle Weakness and Exercise Intolerance

If your senior dog seems to tire more quickly on walks, struggles to climb stairs, or has trouble rising from a lying position, Cushing's could be a factor. Chronic cortisol excess leads to muscle wasting (atrophy), particularly in the hind limbs, which can be hard to distinguish from arthritis and joint pain in senior dogs — and the two conditions can absolutely coexist.

7. Lethargy and Behavioral Changes

General low energy, sleeping more than usual, and decreased interest in play or interaction are common. Some dogs also show increased anxiety, restlessness at night, or seem "mentally foggy" in ways that can overlap with canine cognitive dysfunction (doggy dementia). This overlap makes Cushing's particularly challenging to identify in very old dogs.

8. Panting (Often at Night)

Unexplained, excessive panting — especially at night or when the dog isn't hot or stressed — is a frequently overlooked sign. Cortisol affects respiratory drive and body temperature regulation, leading to chronic panting that puzzles many owners.

9. Recurrent Infections

Because cortisol suppresses immune function, dogs with Cushing's are prone to recurring skin infections, ear infections, and urinary tract infections (UTIs). If your senior dog keeps cycling through the same infections despite treatment, that pattern is worth mentioning to your vet.

10. Slow Wound Healing

Even minor cuts, scrapes, or surgical incisions may take unusually long to heal. This is another consequence of cortisol's protein-depleting effect on skin and connective tissue.

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A Quick Reference: Cushing's vs. Normal Aging

It can feel nearly impossible to separate disease from aging without a vet's help, but here's a general contrast:

Sign	Normal Aging	Cushing's Disease
Thirst/urination	Modest increase possible	Marked, often dramatic increase
Appetite	May decrease	Dramatically increased
Belly shape	Gradual weight change	Pendulous pot belly despite exercise
Hair/coat	Some thinning	Symmetric alopecia, skin changes
Energy	Gradual slowing	Muscle weakness + lethargy
Skin infections	Uncommon	Frequent, recurring

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How Is Cushing's Disease Diagnosed?

If you bring your concerns to your vet, they won't be able to diagnose Cushing's from symptoms alone — multiple conditions can look similar. The diagnostic process typically involves:

Step 1: Routine Bloodwork and Urinalysis

A complete blood count (CBC) and chemistry panel often show classic Cushing's changes: elevated liver enzymes (especially ALP), high cholesterol, and dilute urine. These aren't definitive, but they point strongly in the right direction.

Step 2: Specific Hormonal Testing

Your vet will likely recommend one or more of these tests:

• Low-Dose Dexamethasone Suppression Test (LDDST): The gold standard screening test. A small dose of dexamethasone is given, and cortisol is measured at 4 and 8 hours later. Dogs with Cushing's fail to suppress their cortisol normally.
• ACTH Stimulation Test: Useful for confirming diagnosis and for monitoring treatment. Synthetic ACTH is given and cortisol is measured before and after.
• Urine Cortisol:Creatinine Ratio (UCCR): A simple urine sample taken at home (away from the stress of the clinic). A normal result is reassuring; an abnormal result needs follow-up testing.

Step 3: Differentiating Pituitary vs. Adrenal Form

Once Cushing's is confirmed, your vet may run a High-Dose Dexamethasone Suppression Test (HDDST) or recommend abdominal ultrasound to look at the adrenal glands. An ultrasound can reveal an adrenal tumor and assess its size and characteristics, which influences the treatment plan.

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How Is Cushing's Disease Treated?

Treatment depends on the type of Cushing's and your dog's overall health. Always discuss all options — and their risks — in detail with your veterinarian.

Medical Management (Most Common)

Trilostane (Vetoryl®) is the most commonly prescribed medication in the US for both pituitary- and adrenal-dependent Cushing's. It works by blocking cortisol production in the adrenal glands. It requires regular monitoring because too much reduction in cortisol is just as dangerous as too much — a condition called adrenal insufficiency (Addison's crisis). Dose adjustments are based on ACTH stimulation tests, typically done at 10 days, 4 weeks, and then every 3–6 months.

Mitotane (Lysodren®) is an older alternative that destroys cortisol-producing cells in the adrenal glands. It's less commonly used now but remains a valid option in some cases.

Never adjust medication doses on your own. Both of these drugs have a narrow therapeutic window. Work closely with your vet and keep all scheduled follow-up appointments.

Surgical Options

For adrenal tumors, surgery (adrenalectomy) performed by a veterinary specialist can be curative — but it carries significant anesthetic and surgical risk, especially in senior dogs. Pre-surgical evaluation is thorough, and not every dog is a candidate.

Managing Iatrogenic Cushing's

If corticosteroids are the cause, your vet will create a tapering protocol to slowly wean your dog off the medication. This must be done gradually to prevent a dangerous drop in cortisol.

Radiation Therapy

For dogs with large pituitary tumors causing neurological signs, radiation therapy at a veterinary oncology center can shrink the tumor and improve quality of life, though it doesn't address the hormonal component directly.

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Supporting Your Senior Dog's Quality of Life at Home

A Cushing's diagnosis doesn't mean your dog's best days are behind them. With the right management, many dogs live comfortably for years after diagnosis. Here's how to support them at home:

Hydration and Bathroom Access

Since excessive thirst and urination are prominent, make sure fresh water is always available and that your dog has frequent, reliable bathroom breaks — ideally every 3–4 hours during the day. Doggy doors or indoor pee pads can reduce accidents and the stress associated with them.

Gentle, Consistent Exercise

Muscle wasting is a real concern, but rest alone makes it worse. Short, low-impact walks help preserve muscle mass without overtaxing joints. Avoid hard surfaces and long hikes. Swimming is excellent if your dog tolerates it.

Skin and Coat Care

Brush regularly to stimulate circulation and remove dead coat. Check skin frequently for infections, sores, or calcinosis plaques. Use gentle, fragrance-free shampoos. Report any new skin changes to your vet promptly.

Nutrition

Talk to your vet about what to feed an aging dog since Cushing's dogs often have elevated triglycerides and cholesterol. Avoid free-feeding, as increased appetite can quickly lead to obesity, which worsens joint stress and metabolic burden.

Monitoring at Home

Keep a simple journal noting daily water intake (measuring the bowl before and after can be eye-opening), urination frequency, appetite, energy level, and any new symptoms. This data is genuinely invaluable at follow-up vet appointments.

Emotional Comfort

Senior dogs with Cushing's can feel anxious or restless. Maintain a predictable daily routine, provide comfortable orthopedic bedding, and offer calm, consistent companionship. Anxiety wraps or calming supplements (discussed with your vet first) may help some dogs.

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When to Call Your Vet Immediately

While Cushing's is typically a slow-moving disease, certain situations require urgent veterinary attention:

• Sudden extreme weakness or collapse
• Vomiting, diarrhea, and loss of appetite in a dog on trilostane or mitotane (potential Addisonian crisis)
• Neurological symptoms: seizures, head pressing, walking in circles, sudden blindness
• Rapid worsening of any symptom
• Any sign of a urinary tract infection (straining, blood in urine, crying when urinating)

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The Bottom Line: Trust Your Instincts

You know your dog better than anyone. If something feels "off" — even if each symptom seems minor on its own — trust that instinct. The signs of Cushing's disease in senior dogs tend to accumulate quietly over months before the picture becomes undeniable. The sooner it's caught, the sooner your dog can get relief.

Work closely with your veterinarian, keep those follow-up appointments, and don't hesitate to ask questions. With proper management, a Cushing's diagnosis is not a death sentence — it's the beginning of a more informed, proactive chapter in your senior dog's care.

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⚕️ Important: This article is for information only and isn't a substitute for advice from a licensed veterinarian. Always talk to your vet before changing your senior pet's diet, supplements, or treatment.