What causes a low white blood cell count?

A low WBC count can be caused by a variety of diseases, disorders and conditions, as well as certain medications. In some cases a cause cannot be found.

Diseases and disorders that can cause a low white blood cell count

A low WBC count can be due to a variety of different conditions that either destroy WBCs or inhibit their production in the bone marrow. These include:

  • AIDS

  • Aplastic anemia (condition in which the bone marrow makes insufficient blood cells)

  • Bone marrow disease (myelodysplastic syndromes)

  • Chemotherapy

  • Leukemia

  • Liver disease (hepatitis, cirrhosis, and liver failure)

  • Overactive spleen that destroys white blood cells

  • Radiation exposure

  • Rheumatoid arthritis (chronic autoimmune disease characterized by joint inflammation)

  • Systemic lupus erythematosus (disorder in which the body attacks its own healthy cells and tissues)

  • Viral infection that affects bone marrow function

  • Vitamin deficiency

  • Widespread infection that depletes white blood cells

Medications that can reduce the number of white blood cells

A low WBC count can also be caused by medications or medical treatments that you are receiving for an underlying disease, disorder or condition, such as:

  • Antibiotics

  • Anticonvulsants

  • Antihistamines

  • Antithyroid drugs

  • Arsenic

  • Barbiturates

  • Chemotherapy drugs

  • Diuretics (“water pills”)

  • Radiation therapy

  • Sulfonamides

What are the potential complications of a low white blood cell count?

A poorly controlled or untreated low WBC count can be serious and even life threatening due to increased vulnerability to potentially life-threatening infectious diseases, such as:

  • Bloodstream infection (sepsis)

  • Fungal infection

  • Methicillin-resistant Staphylococcus aureus (MRSA) infection

  • Parasitic diseases

  • Pneumonia

Life-threatening complications of these diseases include:

  • Organ failure

  • Recurrent and resistant infections that are difficult to treat

  • Septic shock

What is a low white blood cell count?

A low white blood cell (WBC) count is a decreased number of white blood cells (leukocytes) in the blood. A low WBC count is referred to medically as leukopenia.

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What other symptoms might occur with a low white blood cell count?

A low WBC count may be accompanied by other symptoms, which vary depending on the underlying disease, disorder or condition. Symptoms can include:

Medical Reviewer: Cynthia Haines, MD Last Annual Review Date: Aug 5, 2013 Copyright: © Copyright 2014 Health Grades, Inc. All rights reserved. May not be reproduced or reprinted without permission from Health Grades, Inc. Use of this information is governed by the HealthGrades User Agreement.

This Article is Filed Under: Heart, Blood and Circulation