Leukocytosis - Causes

Causes

Causes of leukocytosis
Neutrophilic leukocytosis (neutrophilia)	Acute bacterial infections, especially pyogenic infections Sterile inflammation Tissue necrosis Myocardial infarction Burns
Eosinophilic leukocytosis (eosinophilia)	Allergic disorders Asthma Hay fever Drug allergies Allergic skin diseases Pemphigus Dermatitis herpetiformis Parasitic infections Some forms of malignancy Hodgkin's lymphoma Some forms of Non-Hodgkin lymphoma Systemic autoimmune diseases (e.g. SLE) Some forms of vasculitis Cholesterol embolism (transiently)
Basophilic leukocytosis Basophilia	(rare) Myeloproliferative disease, e.g. Chronic myelogenous leukemia
Monocytosis	Chronic infections Tuberculosis Bacterial endocarditis Rickettsiosis Malaria Systemic autoimmune diseases, e.g. SLE Inflammatory bowel diseases, e.g. ulcerative colitis
Lymphocytosis	Chronic infections Tuberculosis Brucellosis Viral infections Hepatitis Cytomegalovirus infection Infectious mononucleosis Pertussis

Leukocytosis is very common in acutely ill patients. It occurs in response to a wide variety of conditions, including viral, bacterial, fungal, or parasitic infection, cancer, hemorrhage, and exposure to certain medications or chemicals including steroids.

For lung diseases such as pneumonia and tuberculosis, WBC count is very important for the diagnosis of the disease, as leukocytosis is usually present.

The mechanism that causes leukocytosis can be of several forms: an increased release of leukocytes from bone marrow storage pools, decreased margination of leukocytes onto vessel walls, decreased extravasation of leukocytes from the vessels into tissues, or an increase in number of precursor cells in the marrow.

Certain medications, including corticosteroids, lithium and beta agonists, may cause leukocytosis.

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