Leukocytosis
Leukocytosis: What You Need to Know
You may notice high while blood cells on a recent lab result and wonder what it means. Leukocytosis is simply a higher-than-normal number of while blood cells (WBCs). It isn't a condition on its own it's your body signaling that something needs attention.
If you're unsure what your results mean, a clinician can walk you through the next steps and help you figure out the cause.
What Is Leukocytosis?
White blood cells (also called Leukocytes) help protect your body from infections, allergens, and other harmful substances. Your bone marrow produces billions each day, and they circulate throughout your bloodstream looking for threats.
When levels rise above the normal range, it may be due to:
- Infection
- Inflammation
- Allergic reactions
- Stress
- Certain medications
- Bone marrow disorders
- Other medical conditions
Leukocytosis may involve one or several white blood cell types, including:
- Neutrophils - most common; respond to bacteria and fungi
- Lymphocytes - fight viruses and abnormal cells
- Monocytes - clean up dead or damaged tissue
- Eosinophils - respond to allergens and parasites
- Basophils - involved in allergic and inflammatory reactions
Types of Leukocytosis
Leukocytosis is grouped by which while blood cell is elevated. Each type points to possible causes:
- Neutrophilia - infection, inflammation, metabolic disorders, blood disorders, some cancers
- Eosinophilia - allergies, medication reactions, parasitic infections
- Monocytosis - autoimmune diseases, bacterial infections
- Lymphocytosis -viral infections, leukemia
- Basophilia - allergies, chronic inflammation, bone marrow disorders
Causes of Leukocytosis
High white blood cell counts may appear due to:
- Allergic reactions
- Autoimmune disorders (such as lupus)
- Bone marrow disorders (including leukemia)
- Chronic inflammation (such as rheumatoid arthritis)
- Emotional or physical stress
- Genetic conditions
- Bacterial, viral, or parasitic infections
- Medications (especially corticosteroids)
- Obesity
- Pregnancy or recent childbirth
- Smoking
- Skin conditions
- Trauma, injury, or recent surgery
- Spleen removal
Signs and Symptoms of Leukocytosis
Symptoms depend on the underlying cause. Some people have no symptoms at all.
Others may notice:
- Fatigue or weakness
- Fever
- Easy bruising or bleeding
- Headaches or dizziness
- Hives or itching
- Shortness of breath or wheezing
- Night sweats
- Loss of appetite
- Unintended weight loss
If symptoms worsen or come suddenly, a medical evaluation can help determine what's going on.
How Is Leukocytosis Diagnosed?
A clinician may review your medical history, symptoms, and medications. Testing often includes:
Primary tests
- Complete blood count (CBC)
- Peripheral blood smear to examine blood cells under a microscope
Additional testing based on results
- Allergy testing
- Autoimmune testing
- Infection testing (bacterial, viral, parasitic)
- Inflammatory markers
Specialized diagnostic procedures
If needed, your clinician may recommend:
- Bone marrow biopsy
- Imaging studies
- Genetic or molecular testing
Treatments for Leukocytosis
Treatment focuses on the underlying cause, not just the lab value. Options may include:
- Medications for allergies, asthma, infection, or inflammation
- Adjusting medications that may be raising WBC counts
- Chemotherapy or radiation for blood cancers
- Leukapheresis, a procedure that removes excess white blood cells
- Stem cell transplant for certain leukemias
A clinician will guide you through what your results mean and what to expect next.
Leukocytosis FAQs
Is leukocytosis serious?
Not always. Sometimes it's a temporary response to infection or stress. Persistent or very high levels may require further testing.
What level of white blood cells is considered high?
A WBC count above 11,000 per microliter is typically considered leukocytosis. Labs may use slightly different ranges.
Can dehydration cause leukocytosis?
Yes. Low fluid levels can make your blood more concentrated, which may temporarily raise WBC levels.
Does leukocytosis go away on its own?
If caused by a mild infection or stress, levels may return to normal once your body recovers.
What is the difference between leukocytosis and leukemia?
Leukocytosis means elevated white blood cells. Leukemia is a cancer that affects how white blood cells form. One does not automatically mean the other.
Related Conditions
- Leukopenia (low white blood cells): Leukopenia means your body has too few white blood cells, which can make it harder to fight infections.
- Neutropenia: Neutropenia is a low level of neutrophils - the while blood cells that protect you from bacterial infections.
- Lymphocytosis vs. lymphopenia: Lymphocytosis is a rise in lymphocytes, while lymphopenia is a drop in them, and both affect how your immune system responds to illness.
- Bone marrow disorders: Bone marrow disorders change how blood cells are produced, sometimes causing unusually high or low white blood cells levels.
- Chronic inflammation: Chronic inflammation keeps the immune system active for long periods, often raising white blood cells counts.
- Infection indicators in lab results: Certain lab results - like high white blood cells or elevated inflammatory markers - can signal that your body is fighting an infection.