Written by Medicover Team and Medically Reviewed by Dr Supriya Lankepillewar, General-medicine

What are the Causes of Increased WBC Count?

White blood cells (WBCs), or leukocytes, are an integral part of the body’s immune system. They help fight infections by targeting bacteria, viruses, and other pathogens that invade the body. Typically, an average WBC count ranges between 4,500 and 11,000 cells per microliter of blood.

However, various factors can lead to an elevated white blood cell (WBC) count, a condition known as leukocytosis. Understanding the reasons for high WBC levels is crucial for accurate diagnosis and effective treatment. In this article, we will delve into the primary causes of increased WBC count.

Infections

Bacterial Infections

One of the most common causes of elevated WBC levels is a bacterial infection. When bacteria invade the body, the immune system responds by producing more white blood cells to combat the disease. Conditions such as bacterial pneumonia, sepsis, and urinary tract infections often result in leukocytosis.

Viral Infections

Viral infections can also stimulate an increase in WBCs. Although the response may not be as pronounced as with bacterial infections, the body still ramps up leukocyte production to fight off viruses such as influenza, hepatitis, and HIV.

Inflammatory Disorders

Autoimmune Diseases

Autoimmune diseases, where the body mistakenly attacks its own tissues, can raise the WBC count. Conditions like rheumatoid arthritis and lupus are known for triggering chronic inflammation, leading to elevated leukocyte levels.

Allergic Reactions

Allergic reactions can also increase WBC count. When the body encounters an allergen, it releases histamines and other chemicals that cause inflammation and attract white blood cells to the site of the reaction.

Bone Marrow Disorders

Leukaemia

Leukemia, a type of cancer that affects the bone marrow and blood, is a significant cause of increased WBC count. In leukemia, the bone marrow produces an excessive number of abnormal white blood cells that do not function properly, leading to various health complications.

Myeloproliferative Disorders

Myeloproliferative disorders are a group of conditions that cause the bone marrow to produce too many blood cells, including white blood cells. Examples include polycythemia vera and essential thrombocythemia. These disorders often lead to elevated WBC levels and require medical intervention.

Stress (Physical or Emotional)

Physical Stress

Physical stress, such as from surgery or trauma, can lead to a temporary increase in WBC count. The body’s response to physical stress includes the release of stress hormones like cortisol, which can stimulate the production of white blood cells.

Emotional Stress

Emotional stress can also impact WBC levels. Chronic stress leads to the release of stress hormones that can affect the immune system, potentially increasing leukocyte count. If stress-related WBC changes concern you, you may visit our Hospitals for proper evaluation.

Tissue Damage

Tissue Damage from Injury or Trauma

Tissue damage resulting from physical trauma, burns, or myocardial infarction (heart attack) is a well-recognized cause of elevated white blood cell (WBC) count. When tissues are injured, the body perceives it as a threat and activates the immune system to initiate repair and defense mechanisms.

Immune Response and WBC Mobilization

This response includes the release of signaling molecules, such as cytokines and chemokines, which attract white blood cells to the affected area. As a result, the bone marrow increases the production and mobilization of WBCs to aid in tissue healing and to help prevent infection at the site of injury.

Immune System Disorders

Leukemia and Blood Cancers

Leukemia is a cancer that causes the bone marrow to produce too many abnormal white blood cells. These cells don’t work well and can weaken the immune system. Other blood cancers like lymphoma and multiple myeloma can also affect white blood cell levels and immune function.

Myeloproliferative Disorders

Myeloproliferative disorders cause the bone marrow to make too many blood cells, including white blood cells. This can lead to high WBC counts and increase the risk of blood clots, stroke, or progression to leukemia if untreated.

Medications

Steroids

Certain medications, particularly corticosteroids, can cause an elevated WBC count. Steroids are often prescribed for their anti-inflammatory effects, but they can also stimulate the bone marrow to produce more white blood cells.

Beta-agonists

Beta-agonists, commonly used to treat asthma and other respiratory conditions, can also lead to an increase in WBC count. These medications stimulate the sympathetic nervous system, which can result in higher leukocyte levels.

Smoking and Substance Use

Tobacco Use

Smoking is a well-documented cause of increased WBC count. The harmful chemicals in tobacco smoke trigger inflammation in the body, leading to a rise in white blood cells as the immune system responds to the damage.

Drug Abuse

Substance abuse, particularly the use of stimulants like cocaine, can also result in leukocytosis. These substances can cause significant physical stress and inflammation, prompting an increase in WBC levels.

Chronic Diseases

Chronic Kidney Disease

Chronic kidney disease (CKD) is associated with elevated WBC counts. The persistent inflammation and immune system dysregulation seen in CKD contribute to higher leukocyte levels.

Chronic Obstructive Pulmonary Disease (COPD)

COPD, a progressive lung disease, often leads to chronic inflammation and recurrent infections, both of which can increase WBC count. The body’s ongoing inflammatory response to lung damage results in elevated leukocyte levels.

Pregnancy

Physiological Changes

Pregnancy induces numerous physiological changes, including a natural increase in WBC count. This elevation is normal and helps prepare the body to protect both the mother and the developing fetus from infections.

Preeclampsia

Preeclampsia, a pregnancy complication characterized by high blood pressure and signs of damage to other organ systems, can also cause an elevated WBC count. The inflammation and stress associated with this condition contribute to higher leukocyte levels.

Conclusion

An increased WBC count can be caused by infections, inflammatory conditions, bone marrow disorders, or stress. Identifying the root cause of leukocytosis is important for accurate diagnosis and effective treatment, improving patient outcomes.

For unexplained leukocytosis, seeking medical evaluation and regular monitoring are crucial to managing the condition. Working closely with healthcare providers can help maintain optimal health and address concerns related to WBC levels.

When to See a Doctor?

An increased WBC count is not a disease itself but a sign that something may be wrong in the body. If blood test results show elevated WBC levels, further investigation is needed to determine the underlying cause. Persistent or unexplained leukocytosis should always be evaluated by a healthcare provider. For help managing high WBC levels, consult our General Physicians.

Frequently Asked Questions