In a dog’s belly, near their kidneys, lives the adrenal gland.
This gland produces a hormone called cortisol which affects the
functions of many organs in the body. Cushing’s disease in dogs, otherwise
known as hyperadrenocorticism, is the overproduction of
cortisol, and is a condition that becomes increasingly likely
as your dog ages. Too much cortisol in the body can cause a
number of problems, including the suppression of a dog’s immune
system, thereby increasing their chances of getting sick.
It can be challenging to diagnose, and a bit complicated to
treat. As with most veterinary health conditions, early
detection, diagnosis, and treatments (like Vetoryl) are incredibly important. Here
are some early warning signs to
look out for.
1. Increased Thirst and Urination
The onset of Cushing’s disease can be a long, slow process. One
of the first signs of this disease is excessive thirst and
urination. You may find that you’re refilling your pet’s water
bowl more often. They may be asking to go outside more
frequently. Paired with this, you may find that your well-trained dog is suddenly having
accidents in the house.
Cushing’s is a disease more often found in older dogs, and as such, at its onset,
these symptoms can sometimes be confused with urinary tract infections or even the
senility that can come with old age. Additionally, increased
thirst could also be a sign of kidney
disease. If increased thirst and urination are paired with
any of the symptoms below, you may want to ask your veterinarian to run
2. Increased Appetite and Weight Gain, Especially with a Pot
Higher levels of cortisone will increase a dog’s appetite. For
this reason, they may eat more, and as a result, gain weight. This weight gain can make it
hard for your dog to move around, jump up on furniture, or even
climb the stairs.
Cortisone will also cause a dog’s abdominal ligaments to relax
and their liver to become bloated -- causing a pot-bellied
As with urinary incontinence,
these effects of Cushing’s can be confused with other issues
elderly dogs commonly face, including arthritis. If you are suspicious of
Cushing’s, ask your vet to feel your dog’s abdomen to see if
their liver is enlarged. Sometimes the result of this simple
hands-on exam will encourage your doctor to do further testing
to either diagnose or rule out the onset of Cushing’s disease.
Panting is normal if a dog has exerted themself, during times
of stress, or if they’re hot. However, if your dog appears to
be panting more than usual, and if this occurs in conjunction
with the other signs mentioned here, it could be an indication
4. Symmetrical Hair Loss
A dog with Cushing’s may lose
fur, although typically, the fur on your dog’s legs and
head will remain intact. Instead, Cushing’s-related hair loss
occurs primarily on a dog’s midsection. Hair loss caused by
Cushing’s is typically symmetrical -- occurring evenly on both
sides of the dog’s body.
5. Thin Skin that Bruises Easily
Try gently pinching a fold of skin on your dog’s abdomen, near
their flank. A dog with Cushing’s may have skin that feels thin
to the touch, as opposed to the plumpness of healthy skin.
Of course, if you notice bruises on your dog, you should tell
6. Recurrence of Infections
Ear and eye infections may occur more and more
frequently in a dog who’s dealing with Cushing’s disease.
7. A Change in Behavior
Many dogs with Cushing's will show a change in behavior, acting
more aggressive, or not as calm as they usually are. Behavioral
changes can signal a whole host of other health problems as
well, so it's always a good idea to alert your vet.
Confusion with Other Conditions
Many of the warning signs mentioned here are also associated
with a number of other ailments that can affect older dogs.
Cushing’s is difficult to diagnose in part because of the
universal nature of many of its symptoms. A few diseases that
could be confused with Cushing’s:
- Urinary incontinence is associated with old age and urinary
- A bloated belly is associated with gastric torsion and
gastric dilation, which if left untreated, can be fatal.
- Hair loss in similarly symmetrical patterns is associated
- Increased thirst and other related symptoms are associated
with the onset of diabetes.
Cushing’s disease is being diagnosed more and more frequently,
so don’t hesitate to ask your vet about looking into this as a
possible cause for your dog’s symptoms.
Dog Cushing's Disease
Cushing's disease, or hyperadrenocorticism, occurs when a dog’s
adrenal glands, located near the stomach and kidneys,
overproduce the hormone cortisol. Cushing’s disease is most
commonly found in elderly dogs, typically 6 years or older, but
it can occur in a dog of any age. Some of the symptoms of
Cushing’s disease are commonly associated with the natural
aging process, which makes testing for the disease very
The pituitary gland produces an adrenocorticotrophic (ACTH)
hormone, which is released into the bloodstream. This hormone
tells the adrenal glands how much cortisol to produce to help
the body handle daily stresses. The pituitary gland senses when
there is enough cortisol in the blood, then stops producing
ACTH in response. Small benign tumors in the pituitary gland
cause the gland to ignore the levels of cortisol, allowing the
overproduction. Small tumors in the adrenal glands can also
cause them to overproduce cortisol, ignoring pituitary control,
poisoning the bloodstream. Unfortunately, Cushing’s disease can
also be caused by extended doses of corticosteroids.
As there is no known way to effectively prevent Cushing’s
disease, it is crucial to perform diagnostic tests early enough
to prevent further damage. As dogs reach middle-age, around
five or six years old, more frequent visits to the veterinarian
for blood tests may become necessary. There are several breeds
that tend to suffer from Cushing’s, such as beagles, Boston
terriers, boxers, dachshunds, and German shepherds, among
Cushing’s Disease Tests Explained
Cortisol/Creatinine Ratio Test can only rule out
Cushing’s disease as a possibility, by comparing the excreted
protein metabolite to normal levels. High cortisol levels in
the urine may indicate high levels in the bloodstream, while
balanced levels rule out Cushing’s disease. Many other
conditions may cause false positives, rendering this test
The ACTH Stimulation
Test first requires a blood sample. The dog is then
injected with the hormone ACTH, stimulating the adrenal glands
to produce cortisol. After a couple hours, blood cortisol
levels are measured and compared to the original blood sample.
A dog with Cushing’s disease has a greater elevation of
cortisol. This test cannot provide information regarding
whether the Cushing’s is pituitary or adrenal.
The Low Dose Dexamethasone
Suppression Test is considered the best test to
diagnose Cushing's disease. First, a blood sample is taken in
the morning. The dog is then injected with a small dose of
dexamethasone, a synthetic glucocorticoid, and samples are
taken again at four hours and eight hours. Dexamethasone
suppresses cortisol production in healthy dogs, but since a
Cushingoid dog lacks the ability to do so, the cortisol levels
remain the same. This test cannot provide information regarding
whether the Cushing’s is pituitary or adrenal.
The High Dose Dexamethasone
Suppression Test may be used to determine whether
the dog has the pituitary or adrenal form of Cushing's. A blood
sample is taken in the morning. The dog is then injected with a
large dose of dexamethasone, and samples are taken again at
four hours and eight hours. Adrenal tumors are indicated by
zero suppression of cortisol, while pituitary tumors may still
have some suppression ability.
Some common symptoms of Cushing’s disease include hair loss
primarily on body, unusually thin skin, propensity for
bruising, hard calcified lumps on skin, lethargy, swollen
belly, increased appetite, thirst, and urination.Some less
common symptoms are sudden difficulty breathing, weakness,
panting, and stiff walking, possibly with paws knuckled over.
Treatment for pituitary dependent Cushing’s disease is often
Lysodren or Mitotane, and Trilostane (aka Vetoryl). These are oral medications
which are to be administered for the rest of the dog’s life.
These medications work to suppress cortisol production in the
adrenal glands. Treatment for adrenal dependent Cushing’s
disease is often surgery to remove the tumor, sometimes in
addition to Trilostane.
More on Senior Dogs
The Best Senior Dog Pet
10 Must-Ask Questions
at Senior Dog Vet Visits
Senior Dog Care: Keeping Your Senior Pet
This information is for informational
purposes only and is not meant as a substitute for the
professional advice of, or diagnosis or treatment by, your
veterinarian with respect to your pet. It has, however, been
verified by a licensed veterinarian for accuracy.