What could cause low white blood cell count

Medically Reviewed By Emelia Arquilla, DO

— Written By Healthgrades Editorial Staff

Updated on January 25, 2022

A low white blood cell (WBC) count, or leukopenia, is a decreased number of WBCs (leukocytes) in the blood. WBCs are an important part of your immune system and your body’s natural weapon to fight off bacteria, viruses, and other germs. When you have a low WBC count, you may be immunosuppressed, which means that you are more vulnerable to potentially serious infections that do not go away on their own or are hard to treat.

This article will outline some causes of a low WBC count. It will explain possible complications of a low WBC count and how to treat and prevent it.

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth.

What can cause a low white blood cell count?

A low WBC count can be caused by a variety of conditions, as well as certain medications. In some cases, there is no known cause.

Conditions that can cause a low white blood cell count

A low WBC count can be due to a variety of different conditions that either destroy WBCs or inhibit their production in the bone marrow. These include:

• Infection: Widespread infection can cause a low WBC count, including viral infections and conditions such as HIV. Malaria can also cause a drop in WBC count.
• Damage to bone marrow: This damage may happen due to an infection, a condition, or a medical treatment, such as chemotherapy.
• Cancers that affect the bone marrow: Such cancers include leukemia and multiple myeloma.
• Autoimmune disorders: These may include lupus and rheumatoid arthritis.
• Hepatitis: This infection attacks WBCs.
• Blood disorders: Agranulocytosis is an example of a blood disorder that can cause a low WBC count.
• Radiation exposure: This can include medical treatments such as radiation therapy.
• Alcoholism: Excess alcohol consumption may lead to low numbers of WBCs.
• Malnutrition: Deficiencies in vitamin B12, folic acid, and overall calories can also cause a low WBC count.

Medications that can reduce the number of white blood cells

A low WBC count can also be the result of medications or medical treatments that a doctor has given you for an underlying condition, such as:

• some antipsychotic treatments
• treatment for overactive thyroid
• antibiotics
• immunosuppressants

Treatments that can lower your WBC count include:

• chemotherapy
• radiation therapy
• bone marrow or stem cell transplants

Symptoms

A low WBC count may accompany other symptoms, which vary depending on the underlying disease, disorder, or condition. Some symptoms can include:

• fever
• chills
• mouth sores
• breathing trouble
• pain in the abdomen or rectum

Seek prompt medical care if you have a low WBC count and have signs of an infection, such as a fever, swollen lymph nodes, a sore throat, or skin lesions.

What are the potential complications of a low white blood cell count?

A poorly controlled or untreated low WBC count can be serious and even life threatening due to increased vulnerability to potentially life threatening infectious diseases, such as:

• bloodstream infection (sepsis) or fungal infection
• methicillin-resistant Staphylococcus aureus (MRSA) infection
• parasitic diseases
• pneumonia

Life threatening complications of these diseases include:

• organ failure
• recurrent and resistant infections that are difficult to treat
• septic shock

Contact your physician if you know you could have a low WCB count due to a condition or previous testing and notice you are experiencing frequent infections.

Anyone who has frequent infections should also contact their doctor to discuss the underlying cause and identify an appropriate treatment method.

Symptoms of an infection

Symptoms of an infection can include:

• fever
• chills
• sore throat
• recurrent mouth sores
• toothache
• rashes
• fatigue
• flu-like symptoms

Diagnosis

A low WBC count may be noticeable during routine testing or through the course of diagnosis and treatment for an underlying condition.

Doctors can check WBC count through lab tests on blood.

Healthy ranges for WBC counts are as follows:

These ranges may vary for children of different ages or people who are pregnant.

Treatment

The correct treatment for low WBC will depend on what has caused the condition.

Often, treatment will involve antibiotics.

Doctors may also recommend treatments that can raise the number of WBCs again. This may involve myeloid growth factors, sometimes called colony-stimulating factors. These proteins help the bone marrow produce more WBCs. These can include:

• filgrastim (Neupogen)
• tbo-filgrastim (Granix)
• pegfilgrastim (Neulasta)

If you are undergoing cancer treatment, doctors may recommend delaying treatment to give your body time to recover its WBC count.

Prevention

Because a low WBC count can be the result of an underlying condition, it is not always possible to prevent it.

However, a person with a low WBC should use the following tips to prevent getting an infection, as this could cause complications:

• Socially distance from people you know are sick.
• Avoid food poisoning by preparing and storing food safely.
• Regularly and thoroughly wash your hands.
• Use an electric shaver rather than a razor when shaving.
• Avoid sharing hot tubs with other people or swimming in rivers or ponds.
• Avoid changing diapers or cleaning animal feces.
• Wear shoes when walking outside.

Learn more tips on preventing infections with a low WBC count.

Summary

A low WBC count may be the result of an underlying condition, such as an infection, blood disorder, or autoimmune condition. If you know you have a low WBC count, try to avoid situations where you could get an infection.

If you experience frequent infections, contact your physician.

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