Low White Blood Cell Count

Complications can cause many symptoms

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Some medical conditions, like bone marrow disease, can cause low white blood cells. These cells are a vital part of the immune system, and having low white blood cells can cause medical problems, especially infections. Low white blood cells can also lead to problems with healing from wounds and make you more susceptible to cancer and other diseases.

This article will discuss the symptoms experienced with a low white blood cell count, what causes the symptoms, risk factors, treatment, and when to contact your healthcare provider.

Cancer patient discusses low white blood cell count with doctor

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Symptoms of Low White Blood Cells 

You wouldn’t expect to have direct symptoms of low white blood cells. But when these cells are low, it causes the immune system to be weak. With a weak immune system, medical problems can arise and these problems will often cause symptoms.

Infections are the most common effect of a low number of white blood cells. The infections can be more frequent and more severe than what you would experience if you had a healthy immune system. Lacking white blood cells can also make it difficult for you to heal from injuries or recover from illnesses.

Symptoms that you may experience from complications (such as infection) of having a low white count include: 

  • Fatigue 
  • Fevers, chills 
  • Sore throat, coughing, difficulty breathing 
  • Nausea, vomiting, diarrhea 
  • Painful urination, blood in the urine, urinary frequency 
  • Skin sores that don’t heal 
  • Mouth sores, mouth pain 

The symptoms that accompany a low white blood cell count can vary and depend on what's causing the low count. For example, a bladder infection can cause urinary symptoms, and a stomach infection can cause nausea and vomiting.

Sometimes a lack of white blood cells leads to opportunistic infections, which are infections that wouldn’t normally develop in a person with a healthy immune system. 

Cancer is another potentially serious effect of low white blood cells. These immune cells normally recognize and destroy abnormal cancer cells, and a white blood cell deficiency can allow cancer cells to multiply and spread in the body. 

Causes of a Low White Blood Cell Count

Common causes of a low white blood cell count are:

  • Medications and cancer treatments, such as some antibiotics, chemotherapy, and radiation therapy
  • Bone marrow cancers and bone marrow disorders, including aplastic anemia and multiple myeloma
  • Infectious diseases, including human immunodeficiency virus (HIV) and severe infections

White blood cells are made in the bone marrow and circulate throughout the body. Diseases, toxins, medications, or medical treatments that harm the bone marrow can prevent enough white blood cells from being produced. Some medical conditions can also cause the destruction of white blood cells.

Usually, having low white blood cells is a sign of chronic disease. But sometimes medications or infections can temporarily cause this problem due to the destruction of white blood cells. This should resolve once the infection clears up or the medication is discontinued.

Benign ethnic neutropenia is a cause of inherited chronic neutropenia (a low number of leukocytes, which are usually the most numerous white blood cells). It is seen mostly in people of African, Middle Eastern, and West Indian descent worldwide. It does not increase a person's risk of infection.

What Medications Cause Low White Blood Cells? 

Some medications can cause low white blood cells as a side effect.

Chemotherapy treatments are the medications most commonly associated with low white blood cells. These medications target rapidly dividing cancer cells, as well as rapidly dividing healthy cells. Radiation therapy, also used as a cancer treatment, can have the same effect.

Because white blood cells rapidly divide as the body frequently replaces them, chemotherapy treatments can prevent their healthy production.

Other medications known to cause low white blood cells include antibiotics, antihypertensives, antipsychotics, immunosuppressants, and anti-epilepsy drugs. These medications do not cause a low white blood cell count in everyone, and there may be a genetic predisposition to this side effect.

How to Treat Low White Blood Cell Symptoms

The symptoms that may develop as a result of having low white blood cells often require treatment in addition to the treatment that’s needed for managing the underlying issues.

Treatments can include:

  • Covering wounds to prevent an infection
  • Tylenol (acetaminophen) or nonsteroidal anti-inflammatories (NSAIDs), such as Advil (ibuprofen) and Aleve (naproxen sodium) for treatment of pain or fevers
  • Fluid intake to prevent dehydration from vomiting or diarrhea
  • Dietary supplements to prevent or treat malnutrition
  • Antibiotics or antivirals to treat infections

Additionally, sometimes a low white blood cell count can be treated, depending on the cause. Examples of treatments may include antiretroviral therapy for treating HIV or a bone marrow transplant for cancer.

Neulasta (pegfilgrastim), a granulocyte colony-stimulating factor (G-CSF), is a medication that can be used in certain circumstances to prevent low white blood cells occurring as a side effect of chemotherapy.

These treatments require ongoing and close medical care.

Are There Tests to Diagnose the Cause of Low White Blood Cells? 

Diagnostic tests can identify the white blood cell count, as well as the cause of low white blood cells. A complete blood count (CBC) is a blood test that measures the number of white blood cells, as well as the number and proportion of each type of white blood cell.

The cause of a low white blood cell count can be identified with diagnostic tests as well. The specific testing selected is directed by the signs, symptoms, and risk factors. For example, an HIV test can identify HIV as the cause, while a bone marrow biopsy can often identify blood cancer.

Known Causes

Sometimes diagnostic tests are not needed to identify the cause of low white blood cells when there is a known cause, such as chemotherapy or radiation therapy. Your white blood cell count may be monitored to identify whether it is too low or is recovering after treatment.

When to See a Healthcare Provider 

If you have been diagnosed with low white blood cells, it’s helpful for you to know the signs of complications and to get medical attention if you start to develop problems. You won’t be able to feel any direct effects of a low white blood cell count, so you may need periodic testing to monitor your count.

Call your healthcare provider or make an appointment if you get a fever or chills, feel run down, develop sores or a wound that won’t heal, or vomit, have diarrhea, or lose your appetite.

Get prompt medical attention for any of the following:

  • Severe vomiting or diarrhea
  • Signs of dehydration—sunken eyes, dry skin, decreased urination
  • Confusion, lethargy
  • Severe pain or swelling
  • Painful, red, or pus-filled wound
  • Shortness of breath

Have an Action Plan

When you have a chronic condition that’s associated with low white blood cells, it’s important for you to have a plan of action in case you begin to develop urgent or nonurgent complications.

If you have a medical condition that causes low white blood cells, it’s important that you maintain consistent medical care. This can include getting regular blood tests to monitor your white blood cell count and surveillance for complications.

You may need symptomatic treatment, as well as treatment of the underlying cause. Some medical conditions that cause low white blood cells are serious chronic illnesses, like HIV or blood cancers.

Coping with these health problems can be overwhelming. Make sure you find ways to reach out for support from your family, friends, healthcare team, or support groups so you won’t have to carry the stress all by yourself.


A low white blood cell count is a consequence of serious diseases, and it can lead to harmful health problems—including infections, slow healing, and cancer. A low white blood cell count doesn’t cause symptoms, but the complications of a low white blood cell count can cause many different symptoms. These symptoms often need to be treated, and management of low white blood cells is important to prevent serious complications.

Frequently Asked Questions

  • Are there medications that increase white blood cells?

    Yes, some medications, called granulocyte colony-stimulating factors (G-CSFs), can increase white blood cells. These are used in specific circumstances, such as to boost white blood cell counts that are reduced by chemotherapy used for treatment of certain types of cancer.

  • Can you feel symptoms of low white blood cells?

    Having a low white blood cell count doesn’t cause detectable symptoms, but the effects of white blood cell deficiency—infections, impaired wound healing, disease, and cancer—can cause a variety of noticeable and distressing symptoms.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Heidi Moawad, MD
Heidi Moawad is a neurologist and expert in the field of brain health and neurological disorders. Dr. Moawad regularly writes and edits health and career content for medical books and publications.