Leukocytosis, or high white blood cell count, can indicate a range of conditions, including infections, inflammation, injury and immune system disorders. A complete blood count (CBC) is usually performed to check for leukocytosis. Treating the underlying condition usually reduces your white blood cell count.
Leukocytosis means you have a high white blood cell count. This means you have more white blood cells than normal. Leukocytosis is a normal immune response and isn’t always a cause for concern. Most of the time, it means that your body is fighting off infection or inflammation. However, there are times when a high white blood cell count could indicate something more serious, such as leukemia.
There are five types of white blood cells (leukocytes), so there are five types of leukocytosis, depending on which type of cell is affected:
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White blood cells are an important and necessary part of your immune system. Produced in your bone marrow, they defend your body against infections and disease. But, when there are too many white blood cells, it usually means you have infection or inflammation in your body. Less commonly, a high white blood cell count could indicate certain blood cancers or bone marrow disorders.
Typically, if there are more than 11,000 white blood cells in a microliter of your blood, it’s considered leukocytosis.
A high blood cell count during pregnancy is normal. Your body is simply experiencing the stress of carrying a baby. Your healthcare provider will run routine blood tests throughout your pregnancy to make sure nothing out of the ordinary is going on.
No. Leukocytosis refers to a high white blood cell count, which can occur for a number of reasons. Rarely, a high white blood cell count can be a symptom of certain blood cancers, such as acute myeloid leukemia, chronic myelogenous leukemia and chronic lymphocytic leukemia.
Many leukocytosis symptoms could indicate an infection or something more serious, such as lymphoma or leukemia. Common warning signs include:
Easy bruising may indicate thrombocytopenia (low platelet count) or severe acute leukemia. In cases of severe acute leukemia, extremely elevated white blood cells can thicken your blood and decrease blood flow. As a result, hyperviscosity syndrome can develop. This condition can cause serious health problems, such as stroke, internal bleeding or vision impairment.
Leukocytosis is most commonly caused by infection or inflammation. Other high white blood cell count causes may include:
Less commonly, leukocytosis is associated with:
Your healthcare provider will perform an exam and ask about your symptoms and medical history. They’ll also order a complete blood count (CBC). This common blood test checks for red blood cells, white blood cells and platelets in your blood. A CBC can tell your healthcare provider if you have certain conditions or infections. In some cases, you might need a bone marrow test to confirm your diagnosis.
Treatment for leukocytosis varies depending on what caused the condition in the first place. For example, if you have a high white blood cell count due to a bacterial infection, then your healthcare provider will prescribe antibiotics. If leukocytosis is associated with an allergic reaction, then you’ll probably need antihistamines. Other common high white blood cell count treatments include:
In some cases, your white blood cell count may return to normal without intervention.
It depends on which type of treatment you receive. In most instances, you can recover from leukocytosis in two to four weeks. If you’re undergoing cancer treatment, it could take longer.
Remember that leukocytosis is a normal immune response, so it doesn’t always need to be prevented. For example, your white blood cells increase when your body needs to fight off infection or inflammation. But, there are things you can do to keep your white blood cell count in a healthy range:
If you have leukocytosis, your healthcare provider will run tests to determine why your white blood cell counts are elevated. Once the root cause has been identified, your healthcare provider will recommend appropriate treatment.
It’s important to call your healthcare provider if something doesn’t seem quite right. Make an appointment if you experience:
If you develop any of the following symptoms, call 911 or head to your nearest emergency room:
A note from Cleveland Clinic
Most of the time, leukocytosis is a normal immune response caused by infection or inflammation. Sometimes, it’s associated with stress, anxiety or pregnancy. In some cases, however, a high white blood cell count could mean something more serious. That’s why it’s important to talk to your healthcare provider. They can determine the cause of leukocytosis and decide whether treatment is necessary.
Last reviewed by a Cleveland Clinic medical professional on 01/19/2022.
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