Decreased production in bone marrow: Neutrophil ganulocytes are primarily produced in the bone marrow. However, hereditary disorders (like congenital neutropenia or cyclic neutropenia), cancer, certain medications, radiation, Vitamin B12 deficiency or folate deficiency may result in a decreased production of these cells.

Increased destruction: If a significant number of neutrophil granulocytes are destroyed, it may also result in neutropenia. For instance, neutropenia is a common side effect of chemotherapy. Chemotherapy-induced neutropenia typically occurs three to seven days after chemotherapy drugs are administered and continues for several days before recovering to normal levels. Conditions like aplastic anemia may also result in neutropenia.

Marginalization and sequestration: Hemodialysis may lead to neutropenia.

Some neutropenic patients, especially those with acute neutropenia, may be asymptomatic or experience mild symptoms. The disease is usually discovered when a patient has developed severe infections or sepsis.

Common symptoms of neutropenia include: skin rash, mouth ulcers, abscesses, thrush, periodontal disease, lymphadenopathy, mucous membrane abnormalities, fever, frequent infections, diarrhea, burning sensation when urinating, unusual redness/pain/swelling around a wound, sore throat, shortness of breath and chills.

Some patients may be asymptomatic or experience mild symptoms. A complete blood count (CBC) test is usually conducted to determine how many and what types of cells are in the blood. Neutropenic patients have an absolute neutrophil count (ANC) that is lower than 1,500 cells per microliter of blood.

In serious cases, a bone marrow biopsy may be performed. During the biopsy, the patient is given a local anesthetic, and a sample of bone marrow is removed with a needle. The sample is then analyzed in the laboratory to determine whether or not the bone marrow is producing a sufficient number of neutrophils.