Your blood is made up of different types of blood cells, including white blood cells (WBCs), which are also known as leukocytes.

WBCs are an important part of your immune system. They help your body fight off diseases and infections. If you have too few WBCs, you have a condition known as leukopenia.

In this article, we take a closer look at leukopenia, including types, symptoms, causes, and treatment.

WBC counts are typically reported as part of a blood test called a complete blood count or CBC. The results can be reported as cells per microliter (μL) of blood or as cells per cubic millimeter (mm3) of blood.

The table below shows the typical ranges of WBCs, according to the Leukemia and Lymphoma Society.

WBCs (per μL of blood)
Men5,000 to 10,000
Women4,500 to 11,000
Children5,000 to 10,000

Generally speaking, when WBC numbers fall below these reference ranges, you have leukopenia. Your doctor will order additional tests to determine what’s leading to your low WBC levels.

It’s important to point out that the exact reference ranges that are used can vary based off the laboratory performing the test. Because of this, always refer to the reference ranges that are listed on the report of your test results.

There are several different types of leukopenia, depending on which type of WBC is low in your blood. The types of WBCs include:

Each WBC type has a different function in protecting your body from infections or harmful substances.

If your blood is low in neutrophils, you have a type of leukopenia known as neutropenia. Neutrophils are the WBCs that protect you from many types of infections, particularly those involving fungi or bacteria.

Neutrophils make up 55 to 70 percent of your total WBC count. Because of this, leukopenia is often caused by a decrease in neutrophils. In fact, some people use the terms “leukopenia” and “neutropenia” interchangeably.

Another common type of leukopenia is lymphocytopenia, which is when you have too few lymphocytes. Lymphocytes are the WBCs that protect you from a variety of infections and also from cancerous cells.

You probably won’t notice any signs of leukopenia. But if your WBC counts are very low, you may have signs of infection, including:

When to seek medical help

If you have any of the symptoms above or experience frequent infections, it’s important to contact a doctor promptly. Also, keep in mind that it’s possible that a fever may be the only symptom of an infection.

Seeking timely medical care for infections is particularly important if you’re at risk for leukopenia. When treatment is received early, it can help to prevent potentially serious complications.

Many diseases and conditions can cause leukopenia, such as:

Blood cell or bone marrow conditions

WBCs originate from the stem cells in the bone marrow. Because of this, conditions affecting blood cells or the bone marrow can lead to leukopenia. Some examples of such conditions include:

Your spleen is also important in the production of WBCs. Splenomegaly, or an enlarged spleen, can also lead to leukopenia.

Treatments for cancer

Cancer treatments are aimed at targeting and eliminating rapidly dividing cancer cells within your body. However, because blood cells also grow rapidly, some cancer treatments can destroy these cells as well. The cancer treatments that may lead to leukopenia include:

Congenital disorders

Congenital disorders are present at birth. The ones that can lead to leukopenia include conditions that affect how bone marrow works to make blood cells, such as:

  • Kostmann syndrome, or severe congenital neutropenia
  • myelokathexis

Infectious diseases

Several infectious diseases that can cause leukopenia include:

Other acute viral infections, such as the flu, or any very severe infection can also lead to leukopenia.

Autoimmune disorders

Some autoimmune disorders can kill WBCs or bone marrow stem cells, which make blood cells, and can lead to leukopenia. Examples of autoimmune disorders that may cause leukopenia are:

Malnutrition

Leukopenia can be caused by vitamin or mineral deficiencies, such as deficiencies in:

Medications

Certain medications can also cause leukopenia as a side effect. Some examples are:

Sarcoidosis

Sarcoidosis is a systemic illness caused by an exaggerated immune response. It’s characterized by the formation of granulomas, or small areas of inflammation, in multiple systems in your body. When these granulomas form in your bone marrow, leukopenia can result.

Anyone who has a condition that can cause leukopenia is at risk.

Leukopenia usually doesn’t lead to noticeable symptoms. Your doctor will monitor your WBC counts carefully if you have any of the conditions that can lead to leukopenia. This means undergoing frequent blood tests.

Because leukopenia involves low levels of infection-fighting immune cells, it can cause some potentially serious complications if left untreated. Some of the complications of leukopenia include:

  • needing to delay cancer treatment because of a mild infection
  • life threatening infections, including septicemia, which is a serious bloodstream infection
  • sepsis, a life threatening response by your body to a blood infection
  • recurrent or prolonged infections
  • premature death

In order to diagnose leukopenia, your doctor will first do a physical exam and get your medical history. They’ll ask you about:

  • what type of symptoms you’re having
  • when your symptoms started
  • whether you have a personal or family history of other health conditions, such as autoimmune disorders or cancers of the blood or bone marrow
  • what types of medications you’re currently taking
  • your lifestyle habits

A complete blood count (CBC) is one of the first tests that’s used to help diagnose leukopenia. This test will inform your doctor about the levels of WBCs, red blood cells, and platelets in your blood.

A CBC can show that your overall levels of WBCs are low. However, your doctor will probably want more details. They’ll likely order a CBC with a differential. A differential breaks down the levels of different types of WBCs, which can help to determine the specific type of WBC that’s low.

Once your WBC count is deemed low, your doctor will order other tests to help determine the cause of your condition. Some examples include:

Treatment for leukopenia depends on which type of WBC is low and what’s causing it to be so. You may also need other treatments to take care of any infections that develop from not having enough WBCs. Common treatments include:

Stopping treatments or medications that cause leukopenia

Sometimes you may need to stop a treatment to give your body time to make more WBCs. Your blood cell counts may naturally rise when treatment like radiation is over or between chemotherapy sessions. The amount of time it takes for WBCs to replenish varies from person to person.

If you’re taking a medication that causes leukopenia, your doctor may adjust the dose that you’re taking. They may also recommend switching to a different medication, if possible.

Treating underlying conditions that cause leukopenia

If you have an underlying health condition that’s causing leukopenia, such as lupus or sarcoidosis, your doctor will develop a treatment plan to manage it. This can help to return your WBCs to typical levels.

Antimicrobials

You may be prescribed medications to prevent an infection or to clear up an existing infection. Some examples include antifungals to treat fungal infections or antibiotics to treat bacterial infections.

Growth factors

Granulocyte colony-stimulating factor and other growth factors derived from bone marrow can help your body to produce more WBCs. Some examples of growth factors that may be used include filgrastim (Neupogen) and pegfilgrastim (Neulasta).

You can’t prevent leukopenia, but can you can take actions to prevent infections when your WBC count is low. Preventative actions include eating well, resting, and avoiding injuries and germs.

Diet

You may have heard of eating an immunocompromised diet, also called a low-bacterial diet or neutropenic diet, if your WBCs are very low. This diet is thought to reduce your chances of getting germs from food or because of the way food is prepared.

However, support for the effectiveness of this diet is lacking. Two 2019 reviews found that the available evidence doesn’t support the use of eating an immunocompromised diet and that such a diet isn’t associated with a decreased infection risk.

Nevertheless, if your WBC counts are low, there are some types of food items that you should try to avoid. These include:

  • raw or undercooked meat, poultry, or seafood
  • raw or undercooked eggs, including foods that contain raw eggs, such as homemade mayonnaise or hollandaise sauce
  • raw or unpasteurized dairy products
  • raw sprouts

It’s also vital to focus on safe food handling in order to reduce your risk of infection. Some tips include:

  • Washing your hands. Wash your hands both before and after handling food as well as before eating.
  • Rinsing fresh produce. Gently rinse fresh produce under running tap water. You can also use a clean brush to scrub the surface of harder produce like apples or potatoes.
  • Separating food types. Try to keep raw food items like meat, seafood, and poultry separate from other foods while storing and preparing them.
  • Checking the temperature. In order to kill disease-causing germs, always cook foods to their safe minimum cooking temperature. You can use a food thermometer to check if an item is cooked all the way through. Safe minimum cooking temperatures can be found here.
  • Cleaning as you go. Be sure to wash all kitchen utensils, cutting boards, and countertops with soap and warm water after using them to prepare food.
  • Refrigerating promptly. Place all perishable foods or leftovers in your refrigerator or freezer in a timely manner. Don’t allow them to sit out on the countertop for extended periods of time.

Lifestyle

There are also ways that you can take care of yourself at home when your WBCs are low. For instance, try these tips to feel better and avoid infections:

  • Washing your hands. In order to avoid infection-causing germs, be sure to wash your hands frequently with soap and warm water. Some examples of when you need to wash your hands include:
    • before touching your nose, mouth, or eyes
    • after being out in public
    • after using the toilet
    • after coughing, sneezing, or blowing your noise
    • before and after handling or preparing food
    • before eating
    • after touching or handling animals
    • after handling garbage
  • Keeping away from germs. Wash your hands throughout the day or use hand sanitizer. Stay away from sick people and crowds, or wear a face mask when in these situations. Don’t change diapers or clean any litter boxes, animal cages, or even a fish bowl.
  • Being very careful. You want to do all you can to avoid even the tiniest of cuts or scrapes because any opening in your skin provides a place for an infection to start. For example:
    • Ask someone else to cut food while you cook or eat.
    • Use an electric razor to avoid nicks if you need to shave.
    • Brush your teeth gently with a soft-bristled toothbrush to avoid irritating your gums.
    • Wear socks or shoes around the house to avoid getting cuts and scrapes on your feet. Always wear shoes when you leave the house.
  • Eating well. Your body needs vitamins and nutrients. Unless your doctor says otherwise, eat plenty of fruits and vegetables. If you have mouth sores or nausea due to a treatment or medication, experiment to find foods you can eat and ask your doctor for help.

Leukopenia is when the levels of WBCs in your blood are lower than average. People with leukopenia are at an increased risk for infections. In fact, you may not know that you have leukopenia until you develop symptoms of an infection like fever or chills.

A variety of conditions can cause leukopenia, including certain types of cancer, infectious diseases, and autoimmune diseases. If you’re at risk of developing leukopenia, your doctor will routinely check your WBC count to help lower your chance of complications.

Depending on the cause, leukopenia can be treated in several ways. While your WBC count is low, you can also make dietary and lifestyle changes to help reduce your risk of infection. If you have leukopenia and symptoms of an infection, contact your doctor right away.