Everything you need to know about Cushing’s disease in dogs
Cushing’s disease is the most common endocrine disorder in dogs. The condition has vague clinical signs that mimic those of other conditions, making Cushing's diagnosis difficult. The condition can be life-threatening, so early detection is key for effective medical management. If you have a dog, read on to learn:
- How do I know if my dog has Cushing’s disease?
- How did my dog get Cushing’s disease?
- How is Cushing’s disease diagnosed and treated in dogs?
- Can canine Cushing’s disease be prevented?
Most Cushing’s cases are caused by tumors on the pituitary gland in the brain. These tumors produce excessive amounts of the hormone that stimulates cortisol production by the adrenal glands, leading to symptoms such as hair loss, excessive urination, and weight loss. With vague and mild early symptoms and a complex blood-testing process, Cushing’s can be difficult to diagnose.
What is canine Cushing’s disease?
The endocrine system controls hormones that regulate biological processes throughout the body, and Cushing’s disease is the most common endocrine disorder in dogs. Also called hyperadrenocorticism, Cushing’s disease occurs when there is too much cortisol in the bloodstream. Cortisol, which is a stress hormone, helps to regulate various essential bodily functions such as metabolism, blood pressure, and immune function. Excessively high cortisol levels can cause widespread symptoms and eventually become life-threatening.
What are the types of Cushing’s disease in dogs?
Cushing’s disease in dogs either results from a tumor on the pituitary gland or adrenal glands as a side effect of prolonged corticosteroid use or from an extremely rare genetic disorder. The majority of cases, about 85%, are due to pituitary tumors.
The pituitary gland in the brain releases a hormone called adrenocorticotropic hormone (ACTH) that stimulates the adrenal glands near the kidneys to produce cortisol. When there is a tumor on the pituitary gland, too much ACTH is produced, causing the adrenal glands to produce excessive cortisol. Adrenal tumors can also cause excessive production of cortisol, though this type of Cushing’s disease is far less common.
Less common forms of Cushing’s disease in dogs include iatrogenic Cushing’s and meal-induced Cushing’s. Iatrogenic Cushing’s occurs as a side effect of steroid use. Steroids are commonly used to treat conditions such as allergies and are an important part of veterinary medicine. However, some dogs on steroid-containing medications develop symptoms consistent with Cushing’s disease. This form of Cushing’s is called “iatrogenic,” meaning it’s caused unintentionally by treatment for another illness. Meal-induced Cushing’s is the result of an extremely rare genetic disorder that causes the release of excess cortisol when a dog eats. The dog food itself or specific ingredients do not cause Cushing’s disease.
What are the clinical signs of Cushing’s disease in dogs?
There is a wide range of behavioral and physical symptoms of Cushing’s disease in dogs. Symptoms are mild and vague at first and can sometimes be brushed off as a normal result of aging or some other minor health condition. Not all dogs exhibit every clinical sign, and symptoms usually become worse over time if the condition is left untreated. Untreated Cushing’s disease can also lead to other health issues and is potentially life-threatening.
Changed habits and activity level
Cortisol regulates many bodily functions that can alter your dog’s habits and level of activity, including:
It’s important to talk to a vet any time you notice changes in your dog’s daily routine, even if you assume those changes are simply a result of their aging. Symptoms such as increased thirst and excessive urination are also symptoms of other conditions such as diabetes and hypothyroidism, so veterinary intervention for diagnostic testing is necessary.
Physical symptoms
Common symptoms of Cushing’s disease cause changes to a dog’s appearance and behavior, such as:
- Bloating or “potbellied” appearance
- Hair loss
- Thin or fragile skin
- Muscle atrophy
- Scaly patches or blackheads on the skin
- Neurological problems such as circling and seizures
- Blindness
Unexplained physical changes should be brought to the attention of a veterinarian. Many of these symptoms, such as hair loss or thinning, occur with other endocrine diseases as well, so diagnostic testing is necessary. Sudden blindness or neurological symptoms may be an emergency.
Can Cushing’s disease lead to other health issues?
Other than the various physical and behavioral clinical signs of Cushing’s disease, the condition can contribute to the development of other health problems in dogs. These conditions can be life-threatening as well and require additional treatment. Cushing’s disease can contribute to developing:
Other health issues that develop as a result of Cushing’s disease require treatment in addition to addressing their underlying cause. A dog develops diabetes, for instance, likely requires lifelong treatment.
How do dogs get Cushing’s disease?
The vast majority of Cushing’s cases in dogs are caused by a pituitary tumor. While it remains unknown why pituitary tumors form, they are most often benign. Adrenal tumors on either of the two adrenal glands can also cause Cushing’s disease. The reason for tumor formation on the adrenal glands is also not well understood, but they are more likely to be malignant when compared with pituitary tumors.
Cushing’s disease can also develop as a side effect of steroid use. Steroid-containing medications are used to treat a variety of conditions in dogs, but the risk for iatrogenic Cushing’s (caused by the medication) goes up with higher doses or a longer duration of treatment.
Meal-induced Cushing’s disease can also occur due to an extremely rare genetic disorder that causes the adrenal glands to release too much cortisol after a dog has eaten. This type of Cushing’s is hereditary and does not develop due to a dog’s diet or any of the ingredients in a dog’s food.
Is my dog at risk for hyperadrenocorticism?
As genetics play a role in the development of Cushing’s disease in dogs, some breeds are more likely to develop the disease than others. Dog breeds that are more likely to develop Cushing’s include:
- Bichon frise
- Jack Russell terrier
- German shepherd
- Dachshund
- Miniature poodle
- Boxer
While these breeds are more susceptible to the condition, a dog of any breed can develop Cushing’s disease.
“Middle-aged and senior dogs are more likely to be diagnosed with Cushing’s disease,” states Dr. Jo Myers, a veterinarian on the Vetster platform. “It is important to get routine wellness checks and testing as recommended by a vet to catch conditions early so they can be treated properly.” Dogs that have conditions requiring high doses or prolonged use of steroids are also at a higher risk of developing iatrogenic Cushing’s disease.
How is Cushing’s disease diagnosed in dogs?
The diagnosis of canine Cushing’s disease involves a physical exam, patient history, and diagnostic testing. A veterinarian may recommend routine blood tests, urinalysis, urine culture, or imaging such as X-rays or an ultrasound. Cushing’s disease cannot be diagnosed only from basic blood work, though the results may suggest the condition. Veterinarians recommend routine diagnostic testing first to rule out other conditions. More complex blood tests, such as an ACTH stimulation test or dexamethasone suppression test, may be recommended if Cushing’s is suspected. These diagnostic tests involve taking multiple blood samples over the course of an hour or more and often need to be sent to an outside lab for results. The necessity for this type of testing contributes to the cost and complexity of diagnosing Cushing’s disease in dogs.
What are the treatment options for dogs with Cushing’s disease?
For all types of Cushing’s disease, drug therapy is the most common treatment for long-term regulation of cortisol production. The majority of dogs have a pituitary tumor causing their Cushing’s disease. Because the pituitary gland is small and located in the brain, surgery to remove the pituitary tumor is usually not practical. However, most dogs with benign pituitary tumors do well with medications to manage their Cushing’s disease. Dogs with adrenal-dependent Cushing’s disease are also often treated with cortisol-regulating medications. Surgery to remove adrenal tumors may be an option for some patients, though this surgery can be risky. Likewise, dogs with meal-induced Cushing’s disease are treated with medications.
Dogs with Cushing’s disease due to steroid use require a gradual discontinuation of corticosteroids. In some cases, iatrogenic Cushing’s disease clears up on its own after steroids are discontinued, and the health issue that was being treated by steroids can be treated in another manner. If Cushing’s disease persists after steroids have been discontinued, the affected dog will also require medication to control cortisol production.
All dogs with Cushing’s disease require diligent follow-up care and close monitoring by a veterinarian to manage symptoms and keep cortisol levels regulated. If levels of cortisol drop too low, Addison’s disease can develop. This routine monitoring requires regular checkups and blood tests with a veterinarian. Surgical intervention for adrenal tumors can be curative if the entire tumor is removed and damage to the adrenal glands is minimal. Drug therapy is a lifelong treatment.
Can I treat my dog at home for Cushing’s disease?
Medication to manage Cushing’s disease can be given at home but must be prescribed by a veterinarian. There are no “natural” treatments for Cushing’s disease, and ongoing veterinary care improves the chances of a good outcome. Surgery, chemotherapy, and radiation for malignant tumors are given in a clinic and may require hospitalization.
Can Cushing’s disease in dogs be prevented?
The vast majority of Cushing’s disease cases cannot be prevented. The condition is primarily genetic and age-related. Iatrogenic Cushing’s can be prevented by careful use of corticosteroids and by using alternatives to steroids prescribed by a vet when long-term treatment is necessary. Dogs who require long-term steroid use must be closely monitored for signs of Cushing’s disease.
What should I do if I think my dog has Cushing’s disease?
Talk to a vet any time you notice changes to your dog’s behavior or physical condition, and do not brush off symptoms simply because your dog is a senior. Cushing’s disease has vague symptoms that are similar to those of many other health issues, including other endocrine disorders. Diagnosing Cushing’s disease or similar conditions in dogs can be a lengthy and complicated process, so be patient and work closely with a veterinarian to get to the bottom of your dog’s symptoms. If you are concerned about your dog’s health and want advice from a veterinary professional, Vetster is available around the clock, so you can schedule an online virtual care appointment at any time.
FAQ - Everything you need to know about Cushing’s disease in dogs
What are common symptoms of Cushing’s disease in dogs?
Common signs of Cushing’s disease in dogs include increased thirst and urination, hair loss or thinning, excessive panting, and a potbellied appearance. Symptoms of Cushing’s disease are vague and can mimic those of other health problems or signs of aging in senior dogs. It’s important to talk to a vet if you notice changes in your dog’s physical condition or behavior.
How long can a dog live with Cushing’s disease?
Dogs can live a normal lifespan with early detection and proper management of Cushing’s disease. Untreated Cushing’s disease can be life-threatening.
How do vets test for Cushing’s disease in dogs?
Cushing’s disease cannot be definitively diagnosed with routine blood tests, but some of the results may suggest the disease. If Cushing’s is suspected, a vet may recommend specific blood tests to assess adrenal function or diagnostic imaging to look for pituitary or adrenal tumors. These tests can be complex and are only useful for ruling Cushing’s disease in or out, so they are not usually recommended unless Cushing’s is suspected.
Can dog food cause Cushing’s disease?
Dog food and ingredients in dog food cannot cause Cushing’s disease. There is a rare genetic disorder that causes Cushing’s disease due to increased cortisol production when a dog eats, but this condition has nothing to do with the type of food the dog is ingesting. Meal-induced Cushing’s disease is extremely rare.
