Educational Content: This article is for informational purposes only and does not constitute medical advice. Always consult a healthcare provider for diagnosis and treatment.

Neutropenia

Medically reviewed by Min Clinic Staff | Updated: January 2026

Neutropenia definition and facts

Symptoms of Neutropenia
Symptoms of neutropenia are fever, skin abscesses, mouth sores, swollen gum, and skin infections.

  • Neutropenia is a condition in which the number of neutrophils (a type of white blood cell) in the bloodstream is decreased, affecting the body's ability to fight off infections.
  • Neutropenia is defined as an absolute neutrophil count (ANC) of less than 1500 per microliter (1500/microL); severe neutropenia is defined as an ANC of less than 500/microL.
  • Neutropenia may be caused by or associated with numerous medical conditions including congenital disorders of the bone marrow, cancer chemotherapy, infections, certain medications (drug-induced neutropenia), and autoimmune disorders.
  • Most infections that occur as complications of neutropenia are due to bacteria that are normally present on the skin or in the gastrointestinal or urinary tract.
  • Treatment depends upon the cause and severity of the condition as well as the underlying disease state responsible for neutropenia.

What is neutropenia?

Neutropenia is a condition in which the number of neutrophils in the bloodstream is decreased. Neutrophils are a type of white blood cell also known as polymorphonuclear leukocytes or PMNs. Neutropenia reduces the body's ability to fight off bacterial infections.

White blood cells are also known as leukocytes. There are five major types of circulating white blood cells:

  1. basophils,
  2. eosinophils,
  3. lymphocytes (T-cells and B-cells,
  4. monocytes, and
  5. neutrophils.

Some white blood cells, called granulocytes, are filled with microscopic granules that are little sacs containing enzymes (compounds that digest microorganisms). Neutrophils, eosinophils, and basophils are all granulocytes and are part of the innate immune system with somewhat nonspecific, broad-based activity. They do not respond exclusively to specific antigens, as do the lymphocytes (B-cells and T-cells).

Neutrophils contain enzymes that help the cell kill and digest microorganisms it has engulfed by a process known as phagocytosis. The mature neutrophil has a segmented nucleus (it is often called a 'seg' or 'poly'), while the immature neutrophil has a band-shape nucleus (it is called a band). Neutrophils are made in the bone marrow and released into the bloodstream. The neutrophil has a life-span of about three days.

What are the signs and symptoms of neutropenia?

Signs and symptoms suggestive of neutropenia include:

  • low-grade fever,
  • skin abscesses,