What Are the Causes of High WBC in Dogs?

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A pet's health relies on white blood cells and a good immune system. Your dog's body produces white blood cells to help combat different types of diseases. Usually, if your veterinarian suspects illness, they'll order a complete blood count to check your dog's white blood cell count levels in their blood stream. If these levels are elevated, chances are they have some kind of infection or inflammatory condition that their body is trying to fight off. Your veterinarian can study these levels to determine just what condition is affecting your dog's health.


Your vet studies your pup's blood test results to determine why he's sick.
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White blood cells fight infections in dogs

Your dog's blood has several different types of white blood cells (WBC), all of which are used to fight off infections and inflammation. These cells are produced in their bone marrow or lymphoid tissue, like the spleen and lymph nodes.


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The five types of white blood cells your dog has are neutrophils, lymphocytes, eosinophils, monocytes, and basophils. Each type of white blood cell works in slightly different ways. The main white blood cells that fight infection are the neutrophils and lymphocytes. Neutrophils, eosinophils, and monocytes all engulf invading particles and infectious agents to neutralize them, while lymphocytes produce special antibodies to destroy these agents. The exact way basophils work is unknown.


Elevated WBC levels in dogs

Leukocytosis is a condition in which your dog's bone marrow and lymph nodes produce more white blood cells than normal. Normal white blood cell values range from 4.0 to 15.5. When reading blood test results, note that the white blood cell count is measured as thousands of cells per cubic milliliter of blood.


If your dog's levels are above 15.5, they may have some kind of infection or inflammatory problem causing their body to produce more white blood cells than usual. The blood test will also show the specific levels of each type of white blood cell, which can help your veterinarian narrow the cause of abnormalities.


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Causes of high WBC in dogs

The main cause of a high white blood cell count in dogs are infections or toxins, although stress and excitement can elevate their values, especially neutrophil and lymphocyte levels. Chronic diseases and infections can also initially elevate your dog's white blood cell count values, which later become low. This is due to the fact that the body can't keep up with the demand for the white blood cells to fight off infectious agents in their body.



Monocyte levels increase with chronic diseases and inflammatory conditions. Dogs with allergies or parasitic infections may have elevated neutrophil, eosinophil, and basophil levels. Dogs with cancers, like lymphocytic leukemia, will have an extremely high white blood cell count level and specifically an elevated lymphocyte count.


Another cause of elevated white blood cell count levels in dogs is an autoimmune disorder, which can cause inflammation in the body, raising their white blood cell count, specifically their neutrophil levels. Cushing's disease in dogs can also cause a high white blood cell count value because it causes their body to produce cortisol, a stress hormone.


Medications that elevate WBC in dogs

Your dog's white blood cell count can become elevated if they've been taking certain medications. Cortecosteroids, like prednisone, can raise their white blood cell count, specifically neutrophil values. If your dog is on any steroid medications, your veterinarian will take this into account when interpreting complete blood count results.

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Dog treatment with the veterinarian

Your veterinarian will determine a treatment plan for the underlying cause of your dog's leukocytosis, which should bring their levels back down to the normal range. They will likely recommend a new blood test after your dog's condition is treated to determine whether or not the treatment is working.

The bottom line

Your dog's white blood cells help them fight off infections. But a blood sample with an elevated white blood cell count can occur for a number of reasons, including various infections, toxins, stress, chronic disease, certain medications, and autoimmune disorders. Your DVM will review bloodwork and have recommended treatments if your dog's white blood cell count is too high.


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