Cushing's disease is one of those diseases that is extremely difficult to detect because the symptoms can be linked to such a wide number of different ailments. Find out here some specific warning signs to look out for as your dog ages.
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 diagnostic tests.
2. Increased Appetite and Weight Gain, Especially with a Pot Bellied Appearance
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 appearance.
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.
3. Panting
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 of Cushing’s.
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 your vet.
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 aggressively or not as calmly 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 tract infections.
- 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 with hypothyroidism.
- 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 important.
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 and then stops producing ACTH in response. Small benign tumors in the pituitary gland cause the gland to ignore the levels of cortisol, allowing overproduction. Small tumors in the adrenal glands can also cause them to overproduce cortisol, ignoring pituitary control and 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 others.
Some common symptoms of Cushing’s disease include hair loss primarily on the body, unusually thin skin, propensity for bruising, hard calcified lumps on the 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.
Types of Cushing’s Syndrome
There are two common forms of Cushing’s syndrome found in dogs.
Almost 80-85% of Cushing’s syndrome diagnosed in dogs are Pituitary-dependent. The condition is caused by a small, benign tumor (adenoma) that forms in the pituitary gland in the brain that produces excessive amounts of ACTH hormone. The hormone signals the adrenal glands produce more cortisol than needed, resulting in the disease.
The second most common type is adrenal-dependent Cushing’s syndrome, which occurs when a tumor forms on one or both adrenal glands, leading to excessive cortisol production. 50% of these tumors are benign (adenomas), while the other 50% can be malignant (carcinomas). About 14-50% of these tumors have a chance of spreading to other organs.
There is a third and less common form called Iatrogenic Cushing’s syndrome, which happens when veterinary doctors administer cortisol as medication.
Diagnosis of Cushing’s Syndrome in Dogs
Diagnosis depends on both behavioral and physical signs and extensive testing. Some of the tests to diagnose Cushing’s disease include -
- Complete blood count (CBC) to examine blood cells
- Blood chemistry panel to understand the condition of vital organs
- Urinalysis to determine the state of kidney function and detect signs of urinary tract infection
- Chest X-rays to assess the condition of the lungs and detect the presence of cancer
- Abdominal ultrasound to check the shape and size of the adrenal glands, the condition of vital abdominal organs, and the presence of tumors
- Blood pressure
The veterinary doctor may also prescribe multiple additional adrenal gland function tests -
- The Urine 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 non-diagnostic.
- 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 of 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.
Treatment of Cushing's Disease in Dogs
The treatment will depend on the type of Cushing’s syndrome. The vet will also decide how to treat the underlying conditions associated with the disease. Cushing’s syndrome can be managed quite effectively if the disease is accurately diagnosed and treated and the dog is diligently monitored. If all goes well, the clinical signs of the disease should start disappearing within a few weeks, but it may take several months before the skin and haircoat conditions improve. These are some of the common treatments used for Cushing’s syndrome in dogs -
Pituitary-dependent treatments
- Trilostane (Vetoryl) - Trilostane or Vetoryl is an FDA-approved oral medication used to treat pituitary-dependent Cushing's syndrome. It decreases the production of cortisol by the adrenal glands. Although this medicine is quite effective, the dog should be diligently monitored due to its potential side effects, which can include lack of appetite, vomiting, diarrhea, and lethargy. In severe cases, the medicine can also destroy the adrenal gland and cause death.
- Mitotane - Mitotane is prescribed off-label for pituitary-dependent Cushing's syndrome. Unlike trilostane, mitotane destroys the adrenal cells responsible for cortisol production, which can be reversed once the disease is cured. However, the drug has the same side effects as Trilostane, so the dog must be closely monitored. Also, the effects of the medicine might be impossible to reverse sometimes, which can cause death.
- Selegiline (Anipryl) - Selegiline was used for pituitary-dependent Cushing's syndrome in the past, but its efficacy is controversial, so some vets don’t prescribe it anymore.
- Radiation therapy for pituitary tumors - Radiation therapy has been used successfully in many cases of larger pituitary tumors (macroadenomas). However, it’s quite expensive, and there’s limited availability, so it may not be an option for many patient dogs.
- Surgical removal of the pituitary tumor - Surgical removal of the pituitary tumor can be done to treat Cushing’s syndrome successfully, but this one’s also quite expensive.
On average, dogs treated with trilostane or mitotane tend to survive 2 to 2.5 years. On the other hand, dogs that undergo surgery or radiation therapy tend to live between 2 to 5 years.
Adrenal-dependent treatments
- Surgical removal of the adrenal tumor (adrenalectomy) - Surgical removal of the adrenal tumor, or adrenalectomy, is considered to be the most effective treatment for adrenal-dependent Cushing's syndrome. However, it is a complex procedure that requires a lot of post-operative monitoring. There’s also the risk of complications like hemorrhage and even death. Generally, smaller tumors are easier to remove than larger ones.
- Medication - Medicines like trilostane or mitotane are also prescribed as pre-surgical medications or to treat adrenal-dependent Cusing’s syndrome when surgery is not possible. The medicines can reduce the clinical symptoms, but they will not improve the condition of the tumor.
10-25% of the dogs that undergo surgery to remove the adrenal glands can die from the operation. The surgery survivors tend to live for 1.5 to 4 years, while the cases treated with medication have an average survival time of 1 year.
Frequently Asked Questions
Does Cushing's cause sores in dogs?
Yes, Cushing’s can cause sores in dogs. Jeff Grognet, a veterinarian in Qualicum Beach, British Columbia, says that dogs with Cushing syndrome can develop calcinosis cutis over time. Calcinosis cutis results from the accumulation of calcium in the epidermis or superficial skin layer and cannot be cured. Skin infections are not uncommon in dogs suffering from Cushing's disease. The condition causes the skin to become thinner, which can lead to infections. Those dealing with Cushing’s are more likely to develop skin infections and health problems. Because of this, dogs develop lesions on their skin. If your dog has Cushing’s, the skin will eventually have sores and become more susceptible to injuries and infections. Existing or new wounds will take a lot of time to heal.
What are the first signs of Cushing's disease in dogs?
The first signs of Cushing’s disease in dogs vary. In most cases, it starts with a case of increased thirst. It feels as if the body is dehydrating. Because of excessive thirst and drinking, it is natural for your dog to urinate more frequently. Dr. Jeff Grognet, a renowned veterinarian, says that pet parents often notice something is wrong when their dog wants to go out to urinate at night. The disease causes an immense increase in thirst (polydipsia) and urination (polyuria) in 80-90% of the dogs. With the progression of the disease, dogs start losing their muscle mass and show signs of weakness. Dog parents may also see signs of skin thinning, lesions, and hair loss. Along with that, you will also notice an increased appetite and obesity in your dog.
Does Cushing’s in dogs cause flaky skin?
Yes, Cushing’s disease in dogs can cause flaky skin. This is when the skin becomes dry. Cushing’s disease can also cause frequent urination, increased hunger and thirst, hair loss, skin infections, etc. You need to remember that Hypothyroidism is another cause of dogs getting flaky skin. Therefore, do not jump to conclusions whether or not your dog has Cushing’s disease just by seeing flaky skin. Consult your vet first before rushing to a conclusion.
How does Cushing's affect a dog's skin?
Cushing’s disease affects your dog's skin by making it flaky. The skin also tends to feel loose and thin. It develops lesions, too. Hair loss is another common issue that can affect your dog’s skin. Hair loss is more prevalent near the neck, flanks, and perineum. Dr. Brittany Lancellotti, DVM, says that Cushing can cause classic cutaneous skin signs similar to those of allergies. However, allergies start to appear when the dog is less than 3 years old, whereas Cushing’s develops in middle-aged or older pets. The latter can cause an onset of skin, ear, or claw fold infections in adult dogs, so if the dog does not have a history of skin allergies, there is a chance of Cushing’s syndrome onset. The disease can cause thinning of hair and skin and the appearance of blackheads. Dog parents may also notice calcium deposits (calcinosis cutis) on the back, neck, shoulders, or in the groin. There might be additional symptoms like a change in hair color, greasy hair, or infection in hair follicles.
What is the life expectancy of a dog with Cushing's disease?
The average expected life expectancy of a dog after being diagnosed with Cushing’s disease is 3 to 6 years. With time, the disease spreads. Your dog’s bones and muscles become weak. They lose all their strength and eventually succumb to the disease. However, that does not mean you should not seek treatment for your dog. Try seeking the necessary treatment and let your vet handle the rest. Dr. Valter Carlos, a veterinary surgeon, says that treatment can make a huge difference in the life expectancy and quality of a dog suffering from Cushing’s syndrome, but it needs to continue lifelong. Untreated dogs can be expected to survive for 6-18 months, which can be reduced further if the tumor turns malignant or starts affecting the brain. The lack of treatment can also severely affect the quality of a dog’s life. On the other hand, dogs that respond well to the treatment can go on to live a normal life as long as the treatment continues. However, some dogs may not respond well to the treatment and might have to be euthanized since that’s the kindest option.
Should I treat my old dog for Cushing's?
Dr. Heather Carleton, a veterinary consultant, says that the decision to treat an old dog with Cushing’s disease should depend on the presence of clinical signs because sometimes, treatment only prevents symptoms like polydipsia (excessive drinking) or polyuria (excessive urination) and does not treat the disease. If there are noticeable symptoms, treatment can positively impact the dog’s quality of life. However, if there are no symptoms, treatment will not affect the dog’s lifespan, so treating your dog may be unnecessary. Your vet should make the decision.
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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.
