Neutropenia (noo-troe-PEE-nee-uh) is an abnormally low count of neutrophils, a type of white blood cell that helps fight off infections, particularly those caused by bacteria and fungi.
The threshold for defining neutropenia varies slightly from one medical practice to another. Neutropenia in adults is generally defined as a count of 1,700 or fewer neutrophils per microliter of blood. The cell count indicating neutropenia in children varies with age.
The lower your neutrophil count, the more vulnerable you are to infectious diseases. If you have severe neutropenia — fewer than about 500 cells per microliter of blood — bacteria normally present in your mouth and digestive tract can cause infections.
Possible causes of neutropenia include:
- Alcoholism or chronic alcohol use
- Aplastic anemia
- Chronic idiopathic neutropenia in adults
- Drugs, such as antibiotics and diuretics
- Hepatitis A
- Hepatitis B
- Hepatitis C
- Hypersplenism, a premature destruction of blood cells by the spleen
- Hyperthyroidism (overactive thyroid)
- Kostmann's syndrome, a congenital disorder involving low neutrophil production
- Lyme disease
- Myelodysplastic syndromes
- Myelokathexis, a congenital disorder involving failure of neutrophils to enter the bloodstream
- Other autoimmune disorders
- Other congenital disorders
- Other infectious diseases
- Other parasitic diseases
- Radiation therapy
- Rheumatoid arthritis
- Salmonella infection
- Syndrome-associated neutropenia
- Vitamin deficiencies
Causes shown here are commonly associated with this symptom. Work with your doctor or other health care professional for an accurate diagnosis.