High White Blood Cell Count

Causes include infection, cancer, and more

White blood cells, also called leukocytes, are an important part of the body’s immune system. These cells help fight infection, aid in healing from trauma, and assist in recovery from disease.

A high white blood cell (WBC) count can develop due to many conditions, including:

This article will discuss symptoms of the conditions associated with a high white blood cell count, including common causes, tests, and treatments. Please see your healthcare provider for specifics regarding your condition.

A fever and feeling run down are symptoms associated with high white blood cells

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Causes of a High White Cell Count

There are several types of white blood cells (neutrophils, lymphocytes, eosinophils, basophils, and monocytes) that act in different ways and may be increased in number in different conditions. A higher-than-normal number of white blood cells is called leukocytosis

When white blood cells are active, they can have several effects. These include:

  • Releasing enzymes that raise the temperature, which causes warmth or fever and sweats 
  • Causing blood vessels to widen and become leaky, which causes redness and swelling
  • Accumulating in certain areas of the body, such as forming an abscess (a walled-off area of infection)

Infections and Inflammation

Infections typically cause a high count of lymphocytes because these cells are the body’s way of eliminating infectious organisms—viruses, bacteria, fungi, and parasites.

Some conditions that can cause a high lymphocyte count include:

  • Tuberculosis, a bacterial infection of the lungs
  • Grave's disease, a thyroid gland disorder
  • Crohn's disease, an inflammatory bowel disease

Conditions that cause inflammation can also cause high WBC counts, such as:

Is a High White Blood Cell Count a Sign of Cancer?

While infections and inflammation are more often the cause for an increase in white blood cell counts, some cancers (lymphoma and lymphocytic leukemia) and bone marrow disorders (polycythemia vera or myelofibrosis) are associated with high WBC count. 

High White Blood Cell Count in Pregnancy

It is normal for the white blood cell count to increase during pregnancy because of the physical stress the body goes through carrying a baby. The levels start to rise during the first trimester, continue to rise into the third trimester, and return to normal within six to eight weeks after delivery.

Other Causes of High White Blood Cell Count

Many medical conditions are also associated with a high white blood cell count, including:

Can Medications Cause a High White Cell Count?

Medications known to increase the WBC count include corticosteroids, lithium, colony-stimulating factors, beta-agonists, and epinephrine.

Symptoms of a High White Blood Cell Count 

Some symptoms may be similar regardless of the cause of a high white blood cell count, while other symptoms will be specific to the underlying condition. In pregnancy, there will likely be no symptoms at all.

Infection and Inflammation Symptoms

  • Fever 
  • Fatigue 
  • Decreased appetite 
  • Sweats 
  • Chills 
  • Swelling of an area of infection
  • Joint swelling due to infection or autoimmune disease 
  • Pain, tenderness, warmth, or redness at an area of infection or joint swelling 
  • Itching, with or without a rash

Cancer Symptoms

If a high WBC count is caused by cancer, symptoms may include:

  • Fever
  • Night sweats
  • Weight loss
  • Bleeding or easy bruising
  • Fatigue
  • Swollen lymph nodes or glands in the neck, armpits, or groin
  • Recurrent infections
  • Shortness of breath

Respiratory Symptoms

If high white blood count is related to a respiratory condition, symptoms may include:

How to Treat a High White Blood Cell Count 

When a high white cell count is caused by an infection that is resolving on its own, as is the case with most viral infections, no medical intervention is needed beyond symptomatic treatment (such as getting rest or drinking warm tea to soothe a sore throat).

Your healthcare provider may suggest ways to relieve the symptoms of the underlying condition that is causing the elevated white cell count. These treatments include:

These treatments may help you feel better, but they might not lower your white blood cell count.

Other treatments that may be needed to treat the underlying condition include:

  • Steroids or immunosuppressants for autoimmune diseases or inflammatory disorders 
  • Chemotherapy or radiation therapy for blood cancer 
  • Bone marrow transplant for some types of blood cancer 
  • Antibiotics or other medications to treat an infection that’s causing a high white cell count 

Some conditions, such as the autoimmune diseases rheumatoid arthritis and lupus or inflammatory bowel disease (IBD, including Crohn's disease and ulcerative colitis), may require ongoing therapy. 

Complications and Risk Factors Associated With a High WBC Count

Blood cancers and autoimmune diseases that cause overproduction of abnormal white blood cells can cause susceptibility to infections and impaired healing from injuries or diseases. 

Sometimes, a high white blood cell count is accompanied by anemia (a low red blood cell count). This happens when bone marrow disease that’s causing overproduction of white blood cells also causes underproduction of red blood cells. 

Are There Tests to Diagnose the Cause of a High WBC Count?

A high white cell count is identified in a blood test called a complete blood count (CBC). This test provides a report of the number of white blood cells and red blood cells, as well as the types of each white blood cell and their percentage. 

What Is a Normal WBC Count?

According to the National Institute of Health (NIH), the normal number of white blood cells in the blood is 4,500 to 11,000 WBCs per microliter (4.5 to 11.0 × 109/L).

In addition to a CBC, you might also have a microscopic examination of your blood sample (peripheral blood smear), which can determine whether the size or shape of the cells is abnormal.

Some conditions, such as autoimmune diseases, can be associated with excess amounts of degenerate neutrophils, which are neutrophils (a type of white blood cell) that are dying. And some types of cancer can cause excess white blood cells that have an unusual microscopic appearance. 

What Is a Dangerous WBC Count?

A white blood cell count is considered high when white blood cell levels exceed 11,000 per microliter (μL) of blood.

When to See a Healthcare Provider 

Call your healthcare provider if you feel sick, run-down, or have a fever for longer than a few days. 

If you have already been diagnosed with a chronic disease that causes a high white cell count, you and your healthcare providers should discuss the signs that your condition is worsening and develop a plan for when you should get medical attention. 

Get prompt medical attention if you develop any of the following:

  • High fever above 103 degrees
  • Sudden or rapidly worsening joint or skin redness, swelling, or pain 
  • Recurrent nausea, vomiting, or diarrhea 
  • Sweats or chills 
  • Dizziness, pale skin, rapid heart rate, or rapid breathing


White blood cells are part of the immune system that help fight infection and help you heal from disease. Your white blood cells can temporarily increase while you are recovering from an illness.

Sometimes, medical problems associated with excess normal or abnormal white blood cells can cause symptoms such as fever, swelling, or congestion. A CBC can measure your white blood cell count. Medications can treat the underlying condition that is causing the elevated white blood cell count.

A Word From Verywell 

Having a high white blood cell count by itself usually is not a reason to worry. This is one of the signs that your body is fighting an infection or recovering from an illness. The chronic or serious illnesses that cause a high white cell count are often treatable with medication or other therapies.

Frequently Asked Questions

  • Does a high white blood cell count always cause symptoms?

    No. It is the underlying disease or condition causing the high WBC that produces symptoms. Symptoms will vary.

  • Is it beneficial to raise your white blood cell count?

    It depends on the underlying condition that is causing a low white blood cell count. It is not beneficial to raise your white blood cell count above normal levels, but if your white blood cell count is low, then you will need treatment to help raise it to normal levels.

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.