Anemia in Dogs

Anemia in dogs, or lack of red blood cells, is rare. In one retrospective study by a veterinary hospital, only 2.9 percent of dogs presented for this condition (1). But if dogs are diagnosed with anemia, it can be life threatening and very costly to treat.

Anemia is caused by many different factors, ranging from trauma to cancer to immune-mediated diseases. Some tick-borne diseases can even cause anemia, which is why using parasite preventatives like Revolution and Simparica TRIO year-round is so important.

Knowing what to look for to catch early signs that your dog is anemic can be a helpful tool in at-home monitoring. This can help prevent the need for blood transfusion, multiple days in the hospital, and, ultimately, create a better outcome for your dog.

What is Dog Anemia?

Anemia in dogs is when the red blood cells circulating in the body are decreased. This lack of red blood cells affects body function, organ systems, and everyday health and is not specific to breed, age, gender, or size.  

When veterinarians see low red blood cells on lab work, there are three reasons that come to mind that could be causing anemia: 

• Blood loss
• Increased red blood cell destruction
• Lack of red blood cell production 

Blood loss can happen due to trauma (e.g., being hit by a car), bleeding tumors, or even an overload of fleas, called flea anemia. 

Destruction of red blood cells can be caused by dog’s immune systems attacking and destroying red blood cells. This might happen due to Immune Mediated Hemolytic Anemia (IMHA), or with blood parasites that attack red blood cells. 

Lack of production of red blood cells can be due to cancer, kidney disease, toxins, or viruses.

Categories of Anemia in Dogs

There are two broad categories when classifying anemia in dogs: regenerative anemia and non-regenerative anemia. These classifications refer to whether or not the bone marrow is making (regenerating) new red blood cells in an appropriate response to the decrease in red blood cells circulating in the bloodstream.

Regenerative anemia is usually caused by blood loss, or destruction of red blood cells in the body. The bone marrow—where red blood cells are made—responds to the lack of red blood cells and will start to produce new ones in response to the low count.

Non-regenerative anemia means that the bone marrow is not responding adequately to the need for more red blood cells. This can be caused by cancers, toxins, or lack of hormone response that signals the marrow to make red blood cells.

What Causes Anemia in Dogs?

As previously mentioned, there can be many causes of anemia in dogs, ranging from blood loss and destruction of red blood cells to toxins or chronic disease. 

Blood Loss

Blood loss may happen as the result of a sudden event, such as being hit by car, a dog fight, surgery, a ruptured tumor, or other trauma. A loss of about 25 percent of a dog’s blood volume can result in shock. Dogs in this state need to be treated by a veterinarian right away, as a blood transfusion could be warranted.

Blood loss could be due to intestinal parasites like hookworms, external parasites like fleas, or chronic bleeding ulcers or tumors. In newborn puppies, a hookworm infection can cause severe anemia as early as one week following birth. 

Destruction of Red Blood Cells

Hemolytic anemias—which are categorized by the destruction of red blood cells—are mainly regenerative, meaning the body responds appropriately when there is a low number of red blood cells, and regenerates red blood cells when the levels get too low.

The most common hemolytic dog anemia we see is Immune Mediated Hemolytic Anemia (IMHA). IMHA is when the body doesn’t recognize its own red blood cells and develops antibodies against them. IMHA can result from infections, medications, vaccines, tumors, or sometimes it develops on its own.

Toxins

Toxins are another cause of regenerative anemias in dogs. If your dog has ingested acetaminophen, onions, heavy metals such as zinc, naproxen, penicillin, or other recent administration of medications or anti-parasitic drugs, be sure to tell your veterinarian. This information can help decipher the cause of your dog’s anemia. 

Many of these toxins cause oxidative damage to a dog’s red blood cells, which results in something called Heinz bodies. Heinz bodies are formed when toxins damage the hemoglobin inside the red blood cells, and therefore the red blood cells become marked for destruction and cleared by the body. This can result in what is known as Heinz-body anemia in dogs.

Chronic Diseases

Chronic diseases in dogs can cause a decrease in the amount of iron available for red blood cell formation. Examples of chronic diseases that interfere with iron availability are tumors, infections, adrenal gland issues, low thyroid, or liver disease.

Dogs with chronic kidney (renal) disease can also develop anemia. The kidney produces a hormone called erythropoietin that sends a signal to the bone marrow to produce more red blood cells. If the diseased kidney isn’t functioning properly, it doesn’t send out the signal to produce more red blood cells, which results in a non-regenerative anemia. 

Cancer or suppression of the bone marrow can cause a lack of production of all blood cells, such as white blood cells, platelets (used for clotting), and red blood cells. 

Other Causes of Anemia in Dogs

Some other potential causes of anemia in dogs include:

• Tick-borne diseases (like Babesia or Ehrlichia)
• Medications (like Chloramphenicol)
• Certain estrogens
• Some chemotherapeutic agents

Symptoms of Anemia in Dogs

Your dog may show a variety of signs depending on if the anemia is chronic or acute (comes on quickly). Pets that have chronic anemia may have milder signs compared to acute cases, as their body may have compensated for the lack of red blood cells over time. 

Signs that could indicate your dog is anemic include: 

• Low energy 
• Fainting or collapsing
• Pale or white gums
• Yellow tinge to skin, gums, or whites of the eyes
• Increased heart rate
• Low blood pressure
• Labored breathing
• Black tarry stool
• Vomiting
• Unsteady on their legs
• Dehydration
• Decreased appetite
• Distended belly
• Generally not feeling like themselves

Diagnosing Dog Anemia 

Diagnosing your dog’s anemia is done at the veterinary clinic or hospital starting with a physical exam of your dog and a complete blood count (CBC). Low levels of red blood cells on blood work is the first indication that something is wrong.  

Your dog’s doctor will also look at young red blood cells called reticulocytes. These can be measured on blood tests to see if the body is trying to produce more red blood cells to compensate for the anemia. If these levels are increased, then the bone marrow is churning out, or regenerating, new red blood cells. By looking at this value on the CBC, we can tell if it is a regenerative or non-regenerative anemia. 

Other diagnostic steps will be aimed at figuring out the root cause. This could include but is not limited to blood chemistry, imaging (X-rays, ultrasound, MRI/CT), endoscopy, viral testing, bone marrow aspirates, and further lab tests.

How to Treat Anemia in Dogs

Treatment will depend on the severity and underlying cause of the anemia. If it is extremely severe, then many dogs will need a blood transfusion. Blood transfusions are given over a few hours, and dogs need to be monitored throughout the process and afterward to make sure there is no adverse reaction, and that they maintain their red blood cell count following the procedure.  

If the cause is a ruptured tumor, then stabilizing the dog and surgically removing the tumor, if possible, is the next step.

IMHA or other immune-related hemolytic anemias can be treated by suppressing a dog’s immune system with medications and steroids. Dogs may need to stay a few nights in the hospital to initially stabilize, and then veterinarians will likely recommend follow-up appointments to test blood counts for the next couple of months.

For flea anemia, treating the dog for fleas and eliminating fleas in the environment is key. Flea anemia is most common in puppies, senior dogs, or immunocompromised dogs.

Cost to Treat Anemia in Dogs

The cost to treat anemia in dogs will depend on the severity of the condition and the cause. Pet parents will need to pay for physical exams, diagnostic testing, and blood work. 

Additionally, blood transfusions and surgeries can cost anywhere from a few hundred dollars to a few thousand. Overnight hospital stays may also be costly. 

How to Prevent Dogs From Becoming Anemic

Because there are so many different things that cause anemia in dogs, there are a variety of prevention tactics you can employ to help protect your pet.

For anemia caused by diseases, the best prevention is to bring your dog to the veterinarian for regular checkups. That way, your vet can run blood work and catch early signs of disease to begin treatment before anemia develops. It’s also important to keep tabs on your dog’s energy level, gum color (they should be nice and pink!), and general disposition. If you pick up on key changes at home and talk to your vet, you may be able to head off anemia before it happens.

Another important prevention method is to ensure your dog is protected against parasites year-round with a proper preventative medication for their age, weight, and the risks in your region.

For example, Revolution is a monthly prescription topical solution that protects your dog from harmful parasites, including fleas and the American dog tick. This can help reduce the risk of flea anemia, as well as anemia caused by American dog tick-borne diseases, like canine babesiosis. It also prevents heartworm disease, ear mites, and sarcoptic mange in dogs.

If you prefer an easy-to-administer, no-mess oral medication, Simparica TRIO is a prescription preventative that comes in a tasty chewable table you give your dog once a month. It protects against ticks, fleas, heartworm disease, roundworms, and hookworms.