Causes of Leukopenia

White blood cells, also known as leukocytes, are the body's natural defense mechanism against infections. According to the National Institutes of Health, normal adults have between 4,500 and 10,000 white blood cells per microliter. When this count drops below 4,500, and particularly below 3,500, this is considered low. Possible causes of a low white blood cell count, also known as leukopenia, include autoimmune conditions, certain types of cancer and cancer treatments, anorexia, and a number of other possible reasons.

One of the most serious causes of leukopenia is a complication involved with cancer treatment. Bone marrow is responsible for producing new blood cells. According to the Mayo Clinic, during chemotherapy and radiation therapy, bone marrow may be damaged. These treatments can cause leukopenia. When the white blood cell count gets too low, the body becomes increasingly susceptible to infection. As such, when these cancer treatments begin to cause a low white blood cell count, treatment is sometimes modified to prevent serious complications from arising.

Similarly, cancers that affect the blood or bone marrow can cause leukopenia. Leukemia is a type of cancer that attacks the bone marrow and blood. The Mayo Clinic reports that leukemia disrupts the normal activity of the bone marrow and its production of blood cells. Leukemia causes the bone marrow to create high quantities of dysfunctional white blood cells, limiting its ability to produce normal blood cells.

Autoimmune disorders are frequent causes of leukopenia. Conditions that cause the body to attack its own cells like HIV/AIDS and lupus can reduce the body's white cell count. White blood cells are attacked early on in an HIV infection. The immune system becomes weaker and weaker, losing its ability to combat even the simplest infections. In lupus, the immune system attacks the body causing pain and swelling in muscles and joints among a number of other varying symptoms. According to the National Institutes of Health, leukopenia exists in about one-fifth of people with lupus.

Anorexia nervosa is can also be the cause of leukopenia. Anorexia nervosa is an eating disorder that involves intentional starvation leading to an abnormally low body weight. According to the University of Virginia Health System, as many as half of all anorexic patients experience a low white blood cell count. This is due to frequent vomiting and a limited diet which prevents the body from obtaining its necessary nutrients.

The possible causes of leukopenia include certain cancers and cancer treatments, autoimmune conditions, certain infections, and a number of other conditions. Anyone with questions or concerns about blood testing, a low blood cell count, or its related conditions should consult their doctor.

References:

Anorexia. University of Virginia Health System.

Leukemia. Mayo Clinic.

Low blood cell counts: Side effect of cancer treatment. Mayo Clinic.