Leukopenia

Overview

Leukopenia means the body has fewer white blood cells (WBCs) than normal. Because WBCs help fight infection, a low count increases the risk of infections and may make it harder for the body to respond to illness.

Sometimes leukopenia occurs when an infection destroys white blood cells, and other times it results from medications, autoimmune diseases, or bone marrow disorders.

A low WBC count is generally defined as below 4,000 cells per microliter, though normal ranges vary by age and sex.

Causes

Leukopenia can develop for several reasons:

Infections

Some infections directly damage or destroy white blood cells, causing levels to drop.

Medications & Medical Treatments

Certain medications (including some used for inflammation, mental health conditions, or cancer) can decrease WBC production.
Chemotherapy and radiation therapy commonly suppress bone marrow activity.

Autoimmune Disorders

Conditions such as lupus or rheumatoid arthritis may cause the immune system to attack WBCs.

Bone Marrow Disorders

Because white blood cells are made in bone marrow, disorders like aplastic anemia, leukemia, lymphoma, myeloma, or myelodysplastic syndromes can lead to leukopenia.

Nutritional Issues

Severe malnutrition or lack of specific vitamins may lower WBC counts.

Symptoms

Leukopenia itself may not cause noticeable symptoms. Instead, symptoms often arise from infections that develop more easily when WBCs are low.

Possible signs include:

Fever

or chills

Feeling weak

tired, or unwell

Frequent or recurrent infections

Sore throat

or cough

Shortness of breath

Dizziness

or faintness

Unexplained weight loss

or poor appetite

Severe leukopenia may lead to serious or long‑lasting infections.

How We Diagnose it

Evaluation includes:

Blood Tests

A complete blood count (CBC) measures the total WBC count.
A WBC differential shows which WBC types are low (e.g., neutrophils, lymphocytes).

Additional Evaluation

If the cause is unclear, your provider may recommend:

A detailed medical history and medication review
Tests for infections or autoimmune diseases
Bone marrow biopsy, especially if a bone marrow disorder is suspected

Treatment Options

Treatment depends on the underlying cause of leukopenia:

Medications may be adjusted if they’re contributing to low WBCs.
Infections are treated with appropriate antivirals, antibiotics, or antifungals.

Infections are treated with appropriate antivirals, antibiotics, or antifungals.

IV fluids
Treatment of inflammation
Safety precautions to reduce infection risk

Rarely, in specific clinical situations, a procedure may be used to remove abnormal or excess white blood cells and return the rest of the blood to the patient.

Living With Leukopenia

Because infection risk is higher, patients should:

Practice good hand hygiene

Avoid people who are sick

Monitor for early signs of infection

Keep up with recommended follow‑up testing

Most cases resolve when the underlying cause is treated, but chronic or severe leukopenia may require long‑term management.

When To See Your Provider

Seek urgent medical care if you experience:

Fever of 100.4°F (38°C) or higher

Chest pain or difficulty breathing

Severe headache, confusion, or sudden weakness

Persistent bleeding or bruising

New pain, swelling, or redness that may indicate infection

Why Choose Illinois CancerCare

A blood disorder diagnosis can feel overwhelming. At Illinois CancerCare, we are committed to ensuring you never have to face it alone. Providing advanced, comprehensive hematology and oncology care for our patients is at the heart of everything we do. Since 1977, our specialists have focused on individualized, evidence-based treatment plans, access to world-class clinical trials, and thorough follow-up. With Illinois CancerCare, you can move forward with confidence knowing trusted expertise and compassionate support are always close to home.‑based treatment plans, access to world‑class clinical trials, and thorough follow‑up.

Sources & Patient Friendly References

Information sourced from Mayo Clinic and Cleveland Clinic.