There are various causes of high WBC. Inflammatory diseases: diseases like bronchitis, asthma, arthritis, or coronary artery disease. Such chronic inflammatory diseases can cause a high WBC. Stress: such as anxiety, overexertion, seizures. Drugs: certain drugs can cause this, such as corticosteroids, lithium, beta agonists. Splenectomy. Leukemoid malignancies: acute leukemias, chronic leukemias, myeloproliferative disorders You need to discuss with your doctor about these conditions. Sometimes the cause of a high WBC cannot be located. High WBC has also been shown to have a higher than average risk. link. I hope this answer was helpful. If you need more information, feel free to ask. For accepting this answer, please click on the green 'accept' button below. Feedback/Bonus will be warmly appreciated.