From the Guidelines
High white blood cell (WBC) count, or leukocytosis, is commonly caused by infections, inflammation, allergic reactions, leukemia, and other blood disorders, as supported by the most recent study 1 from 2023.
Causes of High WBC Count
The causes of a high WBC count can be categorized into several groups, including:
- Infections: Bacterial infections like pneumonia, urinary tract infections, and skin infections often trigger elevated WBC counts as the body fights pathogens.
- Inflammatory conditions: Conditions such as rheumatoid arthritis, inflammatory bowel disease, and vasculitis can also increase WBC levels.
- Allergic reactions: Allergic reactions, including asthma and severe allergies, may cause higher counts, particularly of eosinophils.
- Blood disorders: Blood disorders like leukemia, myeloproliferative disorders, and lymphoma directly affect white blood cell production.
- Other causes: Other causes include physical or emotional stress, certain medications (corticosteroids, epinephrine), smoking, pregnancy, vigorous exercise, and spleen removal.
Importance of Medical Evaluation
The normal WBC range is typically 4,500-11,000 cells per microliter, with values above this indicating leukocytosis. Treatment depends on addressing the underlying cause rather than the elevated count itself, as emphasized in the study from 2024 1. If you have a high WBC count, medical evaluation is necessary to determine the specific cause and appropriate treatment. This evaluation may involve further testing, such as blood work or imaging studies, to determine the underlying cause of the elevated WBC count.
Key Points to Consider
- A high WBC count can be a sign of an underlying infection or inflammatory condition, as noted in the study from 2009 1.
- Leukocytosis can also be caused by blood disorders, such as leukemia, as discussed in the study from 2019 1.
- Medical evaluation is necessary to determine the specific cause of a high WBC count and to guide treatment, as highlighted in the study from 2017 1.
From the Research
Causes of High White Blood Cell (WBC) Count
- Infections, particularly bacterial, can cause a high WBC count, as the body produces more white blood cells to fight off the infection 2, 3
- Nonmalignant causes of leukocytosis include certain medications, asplenia, smoking, obesity, and chronic inflammatory conditions 2
- Physical stress, such as from seizures, anesthesia, or overexertion, and emotional stress can also elevate white blood cell counts 2, 3
- Medications commonly associated with leukocytosis include corticosteroids, lithium, and beta agonists 3
- Primary bone marrow disorders, such as acute leukemias, chronic leukemias, and myeloproliferative disorders, can also cause a high WBC count 3
- Other potential causes of high WBC count include parasitic or allergic conditions, which can cause eosinophilia, and childhood viral illnesses, which can cause lymphocytosis 2
- Certain antibiotics, such as ceftriaxone, can also induce leukocytoclastic vasculitis, a condition characterized by small blood vessel inflammation and skin manifestations 4
Clinical Features and Outcome
- Patients with unexplained or persistent leukocytosis may appear to be in a state of continued inflammation, recently described as the persistent inflammation-immunosuppression and catabolism syndrome (PICS) 5
- These patients often have a prolonged hospital course and may receive extensive use of empiric broad-spectrum antibiotics 5
- The clinical features and outcome of patients with unexplained leukocytosis can vary, but may include symptoms such as fever, weight loss, bruising, or fatigue 2, 3
- In some cases, a high WBC count can be a medical emergency, particularly if the count is above 100,000 per mm3, due to the risk of brain infarction and hemorrhage 3