What Lowers Your WBC? Causes, Risks, and Treatments Explained

November 22, 2025 •

3 min read

According to the Mayo Clinic, a low white blood cell (WBC) count, medically known as leukopenia, can be caused by a variety of conditions, from viral infections like HIV to cancer treatments such as chemotherapy and radiation. It is crucial to understand what lowers your WBC to manage potential health risks and address the underlying cause.

Quick Summary

A low white blood cell count, or leukopenia, results from various factors, including medications, autoimmune disorders, infections, and bone marrow problems. The primary cause must be identified to receive the correct medical treatment.

Key Points

Chemotherapy and radiation are common causes: These cancer treatments suppress bone marrow, where white blood cells are produced.
Autoimmune disorders can lower your WBC: Conditions like lupus and rheumatoid arthritis cause the immune system to attack and destroy white blood cells.
Infections can cause a temporary or severe drop: Viruses like HIV and hepatitis, or a severe bacterial infection like sepsis, can lower WBCs.
Bone marrow diseases impair production: Disorders such as aplastic anemia and leukemia directly affect the bone marrow's ability to produce healthy blood cells.
Nutritional deficiencies play a role: A lack of essential nutrients, including Vitamin B12 and folate, can disrupt proper WBC production.
Low WBC increases infection risk: The primary risk of leukopenia is a heightened susceptibility to infections, which can sometimes be severe.

What Lowers Your WBC: A Comprehensive Overview

White blood cells (WBCs), also known as leukocytes, are a critical part of the body's immune system, fighting off infections and diseases. A low WBC count can leave the body vulnerable to illness, making it essential to understand the potential causes of this condition. While sometimes a temporary issue, persistent leukopenia warrants a full medical evaluation.

Medications and Treatments

Certain medical treatments are known to lower WBC counts. Therapies like chemotherapy and radiation for cancer can damage the bone marrow, where blood cells are produced. Immunosuppressant drugs used for autoimmune diseases or transplants can also reduce WBCs. Additionally, some antibiotics (such as minocycline and beta-lactams) and other medications like antipsychotics, diuretics, and anticonvulsants have been linked to decreased WBC counts.

Infections

While the body typically increases WBCs to fight infection, certain infections can lead to a drop. Viral infections like HIV/AIDS, hepatitis, infectious mononucleosis, and influenza can suppress bone marrow function or directly harm WBCs. Severe bacterial infections, like sepsis, can deplete WBCs faster than the body can produce them. Other infections such as malaria, tuberculosis, and typhoid fever have also been associated with leukopenia.

Bone Marrow Disorders

Problems with the bone marrow, the site of blood cell production, directly impact WBC counts. Conditions like aplastic anemia cause the marrow to stop producing cells. Cancers like leukemia and lymphoma can result in an overproduction of abnormal cells that crowd out healthy ones. Myelodysplastic syndromes, where the bone marrow produces faulty cells, also contribute to low WBCs.

Autoimmune Disorders

In autoimmune diseases, the immune system attacks the body's healthy cells. Sometimes, this includes white blood cells. Conditions like Lupus (Systemic Lupus Erythematosus) and Rheumatoid Arthritis can lead the immune system to destroy WBCs, particularly neutrophils. Autoimmune neutropenia is a specific disorder targeting neutrophils.

Nutritional Deficiencies

Adequate nutrition is essential for producing blood cells. Deficiencies in key vitamins and minerals can hinder this process. A lack of folate and vitamin B12, crucial for blood cell production, can lead to leukopenia. Deficiencies in copper and zinc have also been linked to low WBC counts.

Symptoms and Complications of a Low WBC Count

Mild leukopenia often presents with no symptoms. However, lower counts increase the risk and frequency of infections. Symptoms typically reflect the infections themselves, including fever, chills, body aches, cough, sore throat, or skin/mouth sores. A severely low count poses a higher risk of life-threatening infections such as sepsis.

Comparison of Major Leukopenia Causes


Cause Category	Common Examples	How it Lowers WBC	Typical Onset	Severity	Primary Treatment Approach
Medications	Chemotherapy, Immunosuppressants	Suppresses bone marrow function	Predictable, related to treatment	Often severe	Medication adjustment or growth factors
Infections	HIV, Hepatitis, Sepsis	Directly destroys WBCs or suppresses bone marrow	Sudden (acute infections) or chronic	Varies, can be severe (sepsis)	Antibiotics/antivirals for the infection
Autoimmune Disorders	Lupus, Rheumatoid Arthritis	Immune system attacks and destroys WBCs	Gradual, chronic condition	Variable, chronic issue	Immunosuppressive therapy for the condition
Bone Marrow Issues	Aplastic Anemia, Leukemia	Impairs or disrupts blood cell production	Can be sudden or gradual	Often severe, chronic	Blood transfusions or transplant (serious cases)
Nutritional Deficiencies	B12, Folate, Copper	Reduces the building blocks needed for WBC production	Gradual	Mild to moderate	Dietary changes and supplementation

Conclusion

Identifying what lowers your WBC is vital for managing leukopenia. Causes are varied, from medication side effects to serious health conditions, emphasizing the importance of proper diagnosis. A healthcare provider will determine the cause and tailor a treatment plan, which might involve treating infections, adjusting medications, correcting nutritional deficits, or managing chronic diseases. Supporting immune health through stress management and a healthy diet can also be beneficial.

Always consult a qualified healthcare professional for medical advice. For more patient information on blood disorders, including low white blood cell counts, refer to resources like the MSD Manuals.

Frequently Asked Questions

The medical term for a low white blood cell (WBC) count is leukopenia.

Yes, many medications can lower your WBC count, including chemotherapy drugs, immunosuppressants, some antibiotics, and antipsychotics.

Yes, viral infections such as HIV, hepatitis, influenza, and dengue fever can cause a drop in your WBC count by affecting the bone marrow or destroying white blood cells.

Autoimmune diseases linked to low WBC include lupus (Systemic Lupus Erythematosus) and rheumatoid arthritis, where the immune system attacks its own cells, including WBCs.

Yes, deficiencies in certain nutrients, particularly vitamin B12, folate (folic acid), copper, and zinc, can lead to a low white blood cell count.

The main risk is an increased susceptibility to infections, which can range from mild and frequent to severe and life-threatening, such as sepsis.

Treatment for a low WBC count depends on the underlying cause. It can involve treating the root infection with antibiotics, adjusting or pausing medication, addressing nutritional deficits, or, in severe cases, using growth factors to stimulate bone marrow.