A high white blood cell count can be caused by a variety of factors, including infections, immune system disorders, bone marrow illnesses and certain viruses, according to Mayo Clinic. Cigarette smoking and high stress levels can also cause the body to produce high amounts of white blood cells.
White blood cell counts can also increase following exercise and in response to allergens, pregnancy and asthma, explains Healthline. Medications that can affect white blood cell counts include antihistamines, antibiotics, aspirin and corticosteroids. Symptoms that often accompany high white blood cell counts include fever, body pain and chills. Once the underlying cause of a high white blood cell count is determined, a treatment plan is put into place and individuals are typically required to undergo follow-up testing. If the white cell count remains high following treatment, this can indicate that the illness or infection has worsened.
The five different types of white blood cells in the human body are neutrophils, basophils, monocytes, lymphocytes and eosinophils, according to MedlinePlus. A white cell count of 4,500 to 10,000 cells per microliter is typically considered normal, but these number measurements can vary depending on the testing lab. Low white blood cell counts can indicate certain cancers or liver diseases and bone marrow failure.