White blood cells, also called leukocytes, are an important part of the immune system. They help fight infections and diseases. A low white blood cell count is called leukopenia. It means you have fewer white blood cells than normal. Read on to learn more about the causes, symptoms, diagnosis, and treatment of low white blood cell count.
What is a low white blood cell count?
White blood cells are made in the bone marrow and then released into the bloodstream. There are several types of white blood cells, each with different roles:
- Neutrophils – Fight bacterial infections
- Lymphocytes – Fight viral infections and are involved in immunity
- Monocytes – Engulf and digest pathogens and stimulate other immune cells
- Eosinophils – Fight parasites and are involved in allergic reactions
- Basophils – Release histamine and other chemicals during inflammatory reactions
A normal total white blood cell count ranges between 4,000 and 11,000 cells per microliter of blood. This number can vary slightly from lab to lab.
Leukopenia refers to a total white blood cell count below 4,000 cells per microliter. The lower the white blood cell count, the more severe the leukopenia:
- Mild: 3,000-3,900 cells/microliter
- Moderate: 2,000-2,900 cells/microliter
- Severe: Less than 2,000 cells/microliter
Low counts of specific types of white blood cells have different names:
- Neutropenia refers to low neutrophils
- Lymphocytopenia refers to low lymphocytes
What causes low white blood cell count?
There are many potential causes of leukopenia, including:
- Viral infections, like the flu, mono, hepatitis, or HIV
- Bacterial infections, like tuberculosis
- Autoimmune disorders, like lupus
- Bone marrow disorders, like leukemia or myelofibrosis
- Medications, including antibiotics, anticonvulsants, diuretics, and chemotherapy drugs
- Radiation or chemotherapy treatments for cancer
- Nutritional deficiencies, like low vitamin B12 or folate
- Enlarged spleen, which can trap and destroy white blood cells
- Pregnancy
- Stress
- Hypersplenism
- Sepsis
- Kidney failure
- Liver disease
Identifying the cause of leukopenia directs the treatment. A low white blood cell count on its own without an underlying cause is not necessarily serious. But leukopenia resulting from a disease or condition often requires treatment for the underlying problem.
What are the symptoms of low white blood cell count?
Many people with mild to moderate leukopenia do not have any symptoms. The lower the white blood cell counts, the more likely symptoms will occur. Potential symptoms include:
- Frequent or severe infections
- Fatigue and weakness
- Fever and chills
- Aches and pains
- Sore throat
- Cough
- Shortness of breath
- Nausea, vomiting, and diarrhea
- Skin lesions or rashes
- Bruising or bleeding easily
The most common symptom is an infection that keeps coming back or is difficult to get rid of, like pneumonia, skin infections, cold sores, or urinary tract infections. This occurs because lower white blood cells make it harder for the body to fight off germs.
Who is at risk for low white blood cell count?
Some people are at higher risk of developing leukopenia than others, including:
- People with autoimmune disorders like rheumatoid arthritis or lupus
- People with bone marrow disorders or blood cancers like leukemia
- People undergoing chemotherapy or radiation treatments for cancer
- People taking certain medications long-term like antibiotics, diuretics, anticonvulsants
- Infants born prematurely
- Older adults due to nutritional deficiencies or undiagnosed illnesses
- People with HIV/AIDS
- Alcoholics
- Smokers
- People with kidney failure, liver disease, or enlarged spleen
Talk to your doctor about your risks if you fall into any of these categories. Get routine blood tests to check your white blood cell count. Report any symptoms of infection or illness promptly. Take preventive steps like washing hands frequently, eating a balanced diet, getting enough sleep, and managing stress.
How is low white blood cell count diagnosed?
A complete blood count (CBC) test is usually the first test ordered when leukopenia is suspected. This measures levels of all blood components, including:
- White blood cell count
- White blood cell differential – Breaks the types of leukocytes
- Red blood cell count
- Hemoglobin and hematocrit levels
- Platelet levels
Looking at the differential of white blood cell types can provide clues about the cause. For example, neutropenia may indicate an infection. Additional diagnostic tests may include:
- Blood cultures to look for bacterial or viral infections
- Bone marrow biopsy to evaluate bone marrow function
- Imaging tests like CT scan to look for enlarged spleen
- Vitamin and nutritional tests to check for deficiencies
- Testing for autoimmune disorders
- Urine analysis to look for kidney disease
- Liver function tests
Diagnosing the underlying cause of leukopenia directs the proper treatment.
Is low white blood cell count serious?
The severity depends on the degree of leukopenia and the cause behind it. In general:
- Mild leukopenia (3,000-3,900 cells/microliter) may not cause any issues or require treatment.
- Moderate leukopenia (2,000-2,900 cells/microliter) raises the risks of infections.
- Severe leukopenia (less than 2,000 cells/microliter) can be very serious if it leads to severe infections.
Neutropenia where neutrophil levels are less than 500 cells/microliter is considered the most serious type of leukopenia. Neutrophils fight bacterial infections, so very low levels significantly raise the risks of infections.
The underlying cause also impacts the severity. For example, chemotherapy-induced leukopenia is often short-term, while leukemia can be chronic and life-threatening without treatment. Work with your doctor to determine the severity in your individual case.
How is low white blood cell count treated?
Treatment depends on the suspected cause and severity of leukopenia. Potential treatment approaches include:
- Treating underlying infections with antibiotics or antivirals
- Stopping medications that may be causing it
- Treating underlying autoimmune disorders or cancers
- Taking medications to boost white blood cell production
- Getting growth factors like filgrastim or sargramostim
- Receiving immune globulin therapy
- Improving diet and nutrition
- Getting bone marrow or stem cell transplants in cases of bone marrow failure
- Plasma exchange
- Immunosuppressive drugs like antithymocyte globulin (ATG)
- Treating underlying kidney or liver disease
If an infection occurs, prompt antibiotic treatment can help prevent complications. Preventive antibiotics may be prescribed for people with very low neutrophil counts. Washing hands frequently, avoiding sick contacts, cleaning cuts right away, and having good dental hygiene can also help prevent infections.
What is the outlook for low white blood cell count?
The outlook depends on the severity and cause. With treatment of the underlying condition, many cases of leukopenia resolve completely with a return to normal white blood cell levels.
If an underlying illness like leukemia, kidney disease, or HIV cannot be cured, leukopenia may persist and require ongoing monitoring and care. Severe, chronic leukopenia has a higher risk of serious infections. Work closely with your medical team for monitoring and prevention.
With mild to moderate leukopenia in an otherwise healthy individual, the white blood cell count often returns to normal over weeks to months especially if contributing medications are stopped or infections treated. These cases generally have an excellent long-term outlook.
How can low white blood cell count be prevented?
You may be able to reduce your risk of developing leukopenia by:
- Avoiding or limiting use of medications known to cause leukopenia like antibiotics, diuretics, anticonvulsants, pain relievers, and chemotherapy drugs
- Treating underlying medical conditions promptly
- Eating a balanced, nutrient-rich diet
- Exercising regularly
- Quitting smoking
- Limiting alcohol intake
- Washing hands frequently
- Getting regular physical exams and blood tests
- Getting prompt treatment for any infections
- Avoiding contact with sick people
- Reducing stress
- Getting adequate sleep
However, leukopenia cannot always be prevented – especially if due to genetic conditions, cancer, or autoimmune disorders. Work closely with your doctor for screening and prompt treatment.
Key points
- Leukopenia refers to a low white blood cell count below 4,000 cells/microliter.
- It can be caused by infections, autoimmune disorders, medications, bone marrow disorders, and other conditions.
- Symptoms may include frequent infections, fatigue, fever, and open sores.
- Diagnosis involves a CBC test plus evaluation for underlying causes.
- Treatment depends on the cause but may include antibiotics, medication changes, supplements, or transfusions.
- Outlook varies from excellent recovery to chronic leukopenia depending on cause.
- Prevention involves a healthy lifestyle, prompt infection treatment, and avoiding any contributing medications.
Conclusion
A low white blood cell count does not necessarily indicate a serious problem, especially if mild or moderate. However, very low levels or an underlying condition like cancer or genetic disorders can be extremely serious. Work closely with your doctor for prompt evaluation, treatment, and monitoring if you have leukopenia. With a focused treatment plan, many people recover fully and avoid complications of low white blood cells.