What To Know about Low White Blood Cell Count (Neutropenia)

White blood cells are blood cells that are part of the immune system. They are responsible for ingesting, killing, and digesting harmful pathogens like viruses or bacteria. The body's level of white blood cells is usually measured with a blood test to measure the number of neutrophils, a type of white blood cell. When the neutrophil count is too low, it is known as neutropenia. 

Typically, a low neutrophil count (neutropenia) results in a low white blood cell count, meaning your body does not have enough white blood cells to fight infection. People with a low white blood cell count have lowered immunity levels (immunocompromised). 

Cancer and cancer treatments are common causes of neutropenia. Other possible causes include chronic (long-term) health conditions and infections. Sometimes, the cause is unknown. A low white blood cell count raises the risk of serious infection. Possible symptoms include recurrent infections, fever, chills, and a chronic cough. There are a few ways to treat neutropenia and lower the risk of infection.

Symptoms of Low White Blood Cell Count

A low white blood cell count raises the risk of serious infection. Possible symptoms of chronic infections include:

• Fever
• Chills
• Cough
• Sore throat
• Malaise (generally feeling unwell)
• Mouth sores
• Sores that don’t heal 
• Abdominal pain
• Diarrhea 
• Trouble breathing 

Neutropenia may cause no symptoms at all. Neutrophils cause the immune system reaction of redness and swelling when an area of the body is infected. If your neutrophil count is low, as it would be with neutropenia, then your body might experience infections without you having a strong immune system reaction. Due to the lack of symptoms, you could be unaware you are experiencing an infection. 

Causes

A low white blood cell count occurs when the body does not have enough white blood cells to fight infection. Neutrophils are responsible for ingesting, killing, and digesting harmful viruses, bacteria, and fungi. Cancer is a common cause of neutropenia. 

Cancer treatments like chemotherapy, radiation, bone marrow (stem cell) transplant, and corticosteroids may also cause a low white blood cell count. Most people experience neutropenia about seven to 12 days after chemotherapy. 

Infections that can lead to neutropenia include Helicobacter pylori (H. pylori), human immunodeficiency virus (HIV), and parvovirus B19. Multiple sclerosis is a neurological disorder that may also cause neutropenia. 

Other types of neutropenia are caused by immune disorders, including:

• Lupus
• Rheumatoid arthritis (RA)
• Inflammatory bowel disease (IBD)
• Chronic autoimmune hepatitis  
  

Diagnosing Neutropenia

Your healthcare provider can diagnose neutropenia with a blood test. If you have noticed that you are repeatedly getting sick or experiencing chronic skin infections, your provider may recommend checking your white blood cell count.

A complete blood count (CBC) measures the amount of red blood cells, white blood cells, and platelets in the blood. To determine if you have neutropenia, your provider will review the test results to determine your absolute neutrophil count (ANC). 

A normal range for white blood cells is 4,000-11,000 per microliter (uL) of blood. To find your absolute neutrophil count, your provider would multiply the number of white blood cells by the percentage of neutrophils in your blood.

For example, if your white blood cell count is 8,000/uL and the percentage of neutrophils in the blood is 75%, then your ANC is found by multiplying 8,000 by 0.75, resulting in an ANC of 6,000. A healthy range for the ANC is 2,500-6,000.

People with neutropenia have an ANC lower than 1,000. The risk of serious infection increases significantly when the ANC falls below 500. 

Treatments

The treatment for neutropenia is to first address the cause. For example, if neutropenia is caused by chemotherapy, it will resolve once the treatment stops. 

Treatment options for low white blood cell count include:

• Myeloid growth factors: Sometimes referred to as growth factors or colony-stimulating factors (CSFs), these proteins stimulate the bone marrow to produce more white blood cells. Examples include Neupogen (filgrastim), Granix (tbo-filgrastim), Neulasta (pegfilgrastim), Rolvedon (eflapegrastim), and Ryzneuta (efbemalenograstim alfa).
• Antibiotics: These medications help prevent infection.
• Pausing treatment: If cancer treatments or other medications are causing your neutropenia, your care team may recommend pausing treatment until your ANC increases to a safer level.

Prevention

In many cases, neutropenia cannot be prevented. If you are experiencing neutropenia, your healthcare team will work with you to lower the risk of infection while your immune system is suppressed. 

To prevent infections while you have a low white blood cell count, take the following precautions:

• Wash your hands frequently
• Brush your teeth twice daily
• Avoid people who are sick
• Consider avoiding crowds 
• Wear a mask in public 
• Focus on food safety with proper washing and cooking 
  

Risks of Low White Blood Cell Count

People with neutropenia are at a high risk of infection. Once your level of white blood cells is very low (ANC less than 500), you may experience an infection without the usual symptoms like a fever or swelling. When this occurs, the infection can spread and worsen with no signs. 

Possible complications of neutropenia include:

• Recurrent bacterial or fungal infections
• Sepsis
• Multiorgan failure 
• Antimicrobial resistance 

Living With Low White Blood Cell Count

The prognosis for neutropenia depends on the underlying cause. If your neutropenia is caused by cancer treatment, it will likely resolve once treatment stops. 

While you live with a low white blood cell count, it is important to take precautions to protect yourself from infection. To lower your risk of coming in contact with pathogens, wash your hands frequently, especially after using the bathroom and before eating. Plan to shower every day and brush your teeth twice daily.

When preparing food, wash your hands well and make sure your cooking surface is clean. Do not eat partially cooked food, and immediately store leftovers in the refrigerator. 

Talk with your healthcare provider about which vaccines you need, and ask your family members to stay up to date with their vaccines. Try to avoid spending time with people who are sick, and avoid crowds when your ANC is low. 

A Quick Review

A low white blood cell count occurs when the body does not have enough white blood cells to fight infection. White blood cells are part of the immune system and are responsible for attacking invading pathogens. When you have a low white blood cell count (neutropenia), your risk of infection is high. 

Common causes of neutropenia include cancer and cancer treatments like chemotherapy and radiation therapy. Neutropenia raises the risk of recurrent infections, and symptoms may include fever, chills, diarrhea, and a chronic cough. 

Your healthcare provider can diagnose neutropenia with a blood test called a complete blood count. Treatment for neutropenia includes medications and lifestyle changes to reduce the risk of infection.