White blood cells are an important part of the body’s immune system. High white blood cell counts can be caused by a variety of conditions, including infection, inflammation, allergic reactions, and some forms of cancer.
Infection
One of the most common causes of high white blood cell counts is an infection. When the body is fighting an infection, white blood cells are released to help fight it off. Infections can range from mild, such as a cold, to more serious, such as a bacterial infection.
Inflammation
Inflammation can also trigger an increase in white blood cells. Inflammation is the body’s response to injury or irritation. It can be caused by a variety of conditions, including autoimmune diseases, allergies, and arthritis.
Allergic Reactions
Allergic reactions can also cause an increase in white blood cells. Allergies are the body’s immune system’s response to a foreign substance, such as pollen, animal dander, or certain foods.
Cancer
In some cases, high white blood cell counts can be a sign of cancer. Certain types of cancer, such as leukemia and lymphoma, can cause the body’s white blood cell count to increase.