A macrophage is responsible for many functions, including removing dead or damaged tissue, destroying cancer cells, and regulating the immune response. An increase in white blood cells is known as leukocytosis. It typically occurs in response to the following conditions:. Certain respiratory conditions, such as a whooping cough or tuberculosis , may cause the levels of white blood cells to increase. In some cases, all white blood cells become affected. However, some people have a specific disease in which only one type of white blood cell is affected.
If levels of one particular type of white blood cell increase, this may be due to a specific trigger:. There is, on occasion, no identifiable cause for the increase in white blood cells. This is known as idiopathic hypereosinophilic syndrome. It can lead to serious complications, such as damage to the heart, lung, liver, skin, and nervous system.
White blood cell levels increase significantly during healthy pregnancy because of the physical stress the body endures during this time. The levels start to rise within the first trimester and continue to rise into the third trimester. During labor and in the hours following delivery, white blood cell levels may surge again, to between 9, and 25, white blood cells in every microliter of blood. This is in response to the physical stresses and trauma of labor.
Within 6—8 weeks of delivery, white blood cells return to their normal levels. A doctor may use a blood test to determine levels of white blood cells.
If levels of white blood cells are lower than usual, this may be a sign that the person has reduced immune activity. This can occur as a result of conditions similar to HIV , or immunosuppressant medications.
A deficiency of white blood cells is why people with conditions or medications that suppress the immune system have an increased risk of infection. A number of conditions, collectively known as myeloproliferative disorders, can occur in the bone marrow. These develop when too many immature blood cells are produced, leading to an imbalance. Myeloproliferative disorders are rare conditions that may or may not become malignant.
It begins producing extra white blood cells to fight the infection. Because infection can also lead to inflammation and white cells are produced in response to this, the inflammatory response itself can also be associated with an increase in white blood cell count. Overall, the most common cause for a high white blood cell count is response to infection. Another potential cause of an elevated white blood cell count is leukemia. This is effectively a cancerous change of the blood and bone marrow which causes significant overproduction of white blood cells.
As the lungs and airways become more inflamed, the body creates more white blood cells in response. Raised white blood cell count is itself asymptomatic and therefore any associated features, if present, will typically be associated with the underlying cause. For example, a leukocytosis caused by leukemia may be accompanied by fatigue, general malaise and easy bruising.
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See more conditions. Request Appointment. Symptoms High white blood cell count. Definition Causes When to see a doctor.
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