Causes of Leukocytosis

Luekocytosis literally means abnormal increase in the Leukocytes or the white blood cells. Luekocytosis can be affirmed by if the number of leukocytes that are circulating in the peripheral blood exceeds the Normal White Blood Cell Count of 10,000 white cells per microliter.

As production and release of white blood cells is expected in cases of fighting foreign microorganisms that attempt to invade the body. Luekocytosis can also be caused by disorders in the immune system and by bone marrow tumors.

An increase in the Granulocytes (white blood cells with large granules in their cytoplasm) is noticeable during pregnancy. This increase gets more exaggerated during the labor and the first postpartum week.

Infants and newborns normally have a high count of leukocytes. This high level is very noticeable with neutrophil which drops down within 2 weeks after birth.

Luekocytosis can also be a result of heavy exercises, severe physical or emotional stress, expose to sunlight or cold.

Luekocytosis can be also caused by taking drugs such like Aspirin, Heparin, Quinine, Epinephrine, Triamterene, Chloroform, and Corticosteroids.

Since there are 5 types of Leukocytes, there are also 5 different type of leukocytosis.

The following listing shows the different types of leukocytosis and the threshold values at which the leukocytosis may occur:

  • High Neutrophil count also known as Neutrophilic Leukocytosis or Neutrophilia. It occurs when the count of Neutrophils exceeds 7,500 cells/µL.
  • High Eosinophils count also known as Eosinophilic Leukocytosis or Eosinophilia. It occurs when the count of Eosinophils exceeds 500 cells/µL.
  • High Basophils count also known as Basophilic Leukocytosis or Basophilia. It occurs when the count of Basophils exceeds 50 to 100 cells/µL
  • High Monocyte count also known as Monocytosis. It occurs when the count of Monocytes exceeds 750 cells/µL in children and 500 to 600cells/µL in Adults.
  • High Lymphocytes count also known as Lymphocytosis. It occurs when the count of Lymphocytes exceeds 9000 cells/µL in children under 3 years old, and 7000 cells/µL in children between 4 and 12 years old. For adults Lymphocytosis is defined as the count of Lymphocytes in blood exceeds 4000 cells/µL.