Leukocytosis occurs when the number of leukocytes, commonly known as white blood cells, rises above the normal range. In adults, this usually means a white blood cell count exceeding 11,000 per mm3.
White blood cells are essential for fighting off infections and supporting the body's immune response. A high count often signals that the body is working to combat an underlying issue, such as an active infection.
Identifying the specific cause of leukocytosis is a vital step in determining the most effective treatment plan. Your doctor will typically evaluate these levels alongside other results from a complete blood count (CBC) or additional blood work.
Types of leukocytosis
Because leukocytes refers to a group of several different types of white blood cells, an increase might involve only one specific cell type. There are five primary types of leukocytosis:
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Neutrophilia: This is an increase in neutrophils, which is often triggered by high stress levels, intense physical exercise, diabetes, or certain infections.
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Lymphocytosis: This involves a higher number of lymphocytes and is one of the most common types, typically occurring during recurrent infections like the flu or allergies.
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Monocytosis: This refers to an increase in monocytes and is less common, potentially indicating chronic infections such as tuberculosis, colitis, or even leukemia.
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Eosinophilia: This is an elevation in eosinophils and is most frequently associated with allergic reactions or infections caused by parasites or fungi.
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Basophilia: This is an increase in basophils and is quite rare, sometimes pointing to conditions like asthma, sinusitis, anemia, colitis, or leukemia.
To determine which specific cells are elevated, doctors usually order a white blood cell differential, which is a standard part of a complete blood count (CBC). Normal leukocyte values vary based on a person’s age.
Main causes of leukocytosis
The primary causes of a high white blood cell count include:
1. Infections
Infections, whether viral, fungal, or bacterial, are a leading cause of leukocytosis because they almost always trigger a change in white blood cell levels.
Since there are many different types of infections, a doctor must evaluate your specific symptoms and may order targeted tests to pinpoint the cause. If the source of the infection is unclear, a physician might start a course of antibiotics, as bacterial infections are a common culprit, to see if symptoms improve or cell counts return to normal.
2. Allergies
Allergic conditions, such as asthma, sinusitis, or allergic rhinitis, are frequent causes of increased white blood cell counts, particularly affecting eosinophils and basophils.
In these instances, a doctor might recommend allergy testing to identify specific triggers, especially if your symptoms do not clearly point to a diagnosis on their own.
3. Use of medications
Certain medications, such as lithium or heparin, are known to influence blood cell production and can lead to leukocytosis. It is very important to provide your doctor with a full list of any medications you take regularly whenever your blood work shows abnormalities.
If necessary, your doctor may adjust your dosage or switch you to a different medication that provides the same therapeutic benefit without significantly impacting your blood counts.
4. Chronic inflammation
Chronic or autoimmune diseases, including colitis, rheumatoid arthritis, or irritable bowel syndrome (IBS), can cause persistent inflammation. This prompts the body to produce more white blood cells to address the ongoing issue, meaning patients with these conditions may show leukocytosis even while undergoing treatment.
5. Cancer
While less common, an elevated white blood cell count can sometimes indicate the development of cancer. Leukemia is the most common cancer associated with leukocytosis, though other types, such as lung cancer, can also affect leukocyte levels.
If cancer is suspected, your doctor will order more specialized diagnostic tests to confirm or rule out the condition.
Also recommended: Blood Tests For Cancer: 13 Tests Used For Diagnosis tuasaude.com/en/blood-tests-for-cancerWhat can cause leukocytosis in pregnancy
Leukocytosis is considered relatively normal during pregnancy, with white blood cell counts often increasing naturally throughout gestation to levels as high as 14,000 per mm3. Read more about high white blood cell count during pregnancy and what normal ranges are.
Additionally, counts typically rise further immediately after childbirth due to the physical stress the body undergoes during labor. Because of this, it is common for someone who has recently given birth to show elevated leukocyte levels for several weeks postpartum.