A low white blood cell count, also called leukopenia, may be caused by a variety of health conditions, illnesses, or other related issues. Generally, it is discovered through testing, meaning that a patient is usually already experiencing symptoms that have led him or her to see a medical professional. With so many factors that can cause a low white blood cell count, it is important to get comprehensive tests that can lead to an accurate diagnosis of the underlying cause.
White blood cells, also called leukocytes, are the warriors of the immune system. Mostly produced by bone marrow, white blood cell count will initially rise when the body is attacked by a disease. If the infection is overwhelming, however, white blood cells may be consumed faster than they can be released, leading to a low count. Additionally, if an infection is disturbing the functions of the bone marrow, production may be slowed down and white blood cell count may drop. In a healthy adult, white blood cells account for about 1% of blood makeup, but this proportion varies with age and even sex.
Sometimes, a low white blood cell count is attributed to medication or treatment. Certain intensive medication therapies, such as cancer-fighting chemotherapy, will destroy white blood cells as well as cancerous cells. People undergoing chemotherapy are carefully monitored to ensure that their white blood cell count stays above a minimum level, as too great a drop leads to a high risk of infection and other complications. Radiation therapy, another type of cancer treatment, can also destroy healthy white blood cells along with diseased, cancerous cells.
A low white blood cell count is frequently a result of a viral infection or congenital defect that slows down bone marrow function. Without bone marrow producing white blood cells, any minor infection can quickly spread in the wake of a weak defense. Some congenital issues considered possible causes of decreased white blood production include myleokathexis and Kostmann's syndrome.
Autoimmune diseases are conditions that lead the body to attack its own defense system. As the body turns inward, white blood cells can become a major victim of the battle as they attempt to attack the organs and tissues of the body instead of infections. Lupus and HIV/AIDS are two common autoimmune diseases associated with a low white blood cell count.
In some cases, a vitamin or mineral deficiency can cause the white blood cell count to drop significantly. This is commonly associated with a copper and zinc deficiency, though a low red and white blood cell count may also be due to a lack of iron or vitamin B12 in the diet. Adding a daily vitamin supplement or changing diet to include more vitamin-rich foods can sometimes boost a vitamin-deficiency caused low blood cell count.