From the Guidelines
A drop in total white blood cell count from 11,000/μL to a lower value could be caused by various factors, including resolution of an infection or inflammatory process, response to medication, recovery from stress, or bone marrow suppression. The most recent and highest quality study 1 suggests that hematologic abnormalities, such as leukopenia, can be a manifestation of sarcoidosis, which may raise the possibility of bone marrow involvement. However, this is not the most common cause of such abnormalities. Some potential causes of a drop in white blood cell count include:
- Resolution of an infection or inflammatory process, as white blood cells typically increase during these conditions and return to normal afterward
- Response to medication, particularly if the person was taking steroids or other anti-inflammatory drugs that were discontinued
- Recovery from stress, as physical or emotional stress can temporarily elevate white cell counts
- Bone marrow suppression from medications like chemotherapy, certain infections that deplete white cells, autoimmune disorders, or nutritional deficiencies It is essential to note that the clinical significance of a drop in white blood cell count depends on how far the count has dropped, how quickly it occurred, and the person's overall health status. If the count drops significantly below the normal range (below 4,000/μL), it could indicate a more severe underlying condition, such as bone marrow suppression or an autoimmune disorder. In such cases, medical evaluation is warranted, particularly if accompanied by symptoms like fever, fatigue, or recurrent infections. Regular monitoring of white cell counts is crucial for anyone experiencing unexplained decreases to determine if intervention is needed, as suggested by the study 1.
From the Research
Possible Causes of a Drop in Total White Blood Cell (WBC) Count
- A drop in total WBC count can be caused by various factors, including bone marrow hypoplasia, which is a rare feature of Brucella infection 2.
- Infections such as brucellosis can lead to pancytopenia, a condition characterized by a decrease in the number of red and white blood cells, as well as platelets 2.
- Certain medications, asplenia, smoking, obesity, and chronic inflammatory conditions can also cause a decrease in WBC count 3.
- A decrease in WBC count can also be a sign of a hematologic malignancy, such as leukemia, or a symptom of other conditions like anemia or cancer 4, 3.
Role of Bone Marrow in WBC Production
- Bone marrow plays a crucial role in the production of WBCs, producing approximately 500 billion new blood cells daily to maintain steady-state levels in the peripheral circulation 4.
- The output of bone marrow is measured using the complete blood count (CBC), which can help diagnose conditions such as anemia, cancer, infection, or immunodeficiencies 4.