What Are the Causes of High WBC in Dogs?

By Susan Paretts

Your pup's body produces white blood cells to help combat different types of diseases. Usually, if your vet suspects he's sick, she'll order a complete blood count to check his white blood cell count levels. If these levels are elevated, chances are he has some kind of infection or inflammatory condition, which his body is trying to fight off. Your vet can study these levels to determine just what that condition is.

The White Blood Cells

Your pup has several different types of white blood cells in his body, all of which are used to fight off infections and inflammation. These cells are produced in your pup's bone marrow or lymphoid tissue like the spleen and lymph nodes. The five types of white blood cells your pup 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, according to PetEducation.com.

Elevated WBC Levels

Leukocytosis is a condition in which your pup'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, according to veterinarian Ron Hines of the 2ndchance.info website. When reading his blood test results, note that the white blood cell count is measured as thousands of cells per cubic milliliter of blood. If your pup's levels are above 15.5, he may have some kind of infection or inflammatory problem causing his body to produce more white blood cells than usual. The blood test also will show the specific levels of each type of white blood cell, which can help your vet narrow the cause of his elevated white blood cells.

Causes of High WBC in Dogs

The main cause of a high white blood cell count in pups are infections or toxins, although stress and excitement can elevate your pup's values, especially his neutrophil and lymphocyte levels. Monocyte levels increase with chronic diseases and inflammatory conditions. Pups with allergies or parasitic infestations 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 your pup's white blood cell count and specifically his neutrophil levels. Cushing’s disease in dogs also may cause a high white blood cell count value because it causes his body to produce cortisol, a stress hormone.

Medications that Elevate WBC

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

Treatment with the Vet

Your vet will determine a treatment plan for the underlying cause of your pup's leukocytosis, which should bring his levels back down to the normal range. Chronic diseases and infections 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 his body. Your vet likely will recommend a new blood test after your pup is treated for his condition to determine whether or not the treatment is working.