Neutropenia is a condition in which the body does not have enough neutrophils — a type of white blood cell that helps the body to fight bacterial infections. Neutropenia is defined as having an absolute neutrophil count of less than 1500/μL. The absolute neutrophil count (ANC) is calculated by multiplying the total white blood cell count by the percentage of neutrophils and band cells (which also are a type of white blood cell, important in helping to fight acute infections).

Severity of the Condition Defined:

• Mild neutropenia: The ANC ranges between 1000-1500/μL
• Moderate neutropenia: The ANC ranges between 500-1000/μL
• Severe neutropenia: The ANC is less than 500/μL

What Causes Neutropenia?

The most common causes of neutropenia are viral infections (such as chicken pox or the flu). If children are neutropenic at the time of an acute viral infection, a repeat CBC should be obtained three to four weeks later to evaluate for resolution of neutropenia.

In rare cases, serial CBC's over the course of six to eight weeks and/or antibody testing may be necessary to help evaluate for causes of neutropenia in children.

Common Disorders/Causes from Outside the Bone Marrow

• Infection
• Medications (such as penicillin, propylthiouracil, phenothiazine, anti-seizure medications)
• Antibody-mediated (such as auto-immune neutropenia)
• Enlarged spleen
• Nutritional deficiency (such as folate or B-12 deficiency)

Rare Disorders/Causes from Within the Bone Marrow Itself

• Cyclic neutropenia–Characterized by cycling of the neutrophil count
• Severe congenital neutropenia–Associated with very low neutrophil counts and frequent, severe infections
• Bone marrow infiltration–Malignancies that invade the bone marrow (such as leukemia)

Syndrome-associated neutropenia (e.g. Schwachman-Diamond, Dyskeratosis congenita)

• Idiopathic neutropenia (unknown causes)

How Is Neutropenia Diagnosed?

Neutropenia is diagnosed by obtaining a complete blood count (CBC) and calculating the ANC. Neutropenia is diagnosed if the ANC is less than 1500/μL. It is important to note, however, that only those patients who have severe, chronic neutropenia are likely to develop life-threatening infections.

In addition to a laboratory assessment, neutropenia patients may have a history of frequent/recurrent infections, lung infections, chronic ear infections, skin infections, serious infections (e.g., meningitis, or bone infections) or chronic mouth ulcers. Occasionally there may be a history of family members who may have died in infancy due to acute infections.

What Are the Symptoms of Neutropenia?

• Frequent infections
• Serious respiratory infections, including pneumonia or sinus infections
• Skin infections (e.g., cellulitis, abscesses)
• Multiple serious infections (e.g., meningitis, bone infections)
• Lymph node infections
• Gum disease
• Mouth sores/ulcers
• Vaginal, urethral rectal ulcers

How Is Neutropenia Treated?

• Observation
• Antibiotics, if appropriate for bacterial infections
• In very rare cases, injections of a growth factor for WBCs

Important note: patients who are diagnosed with neutropenia should be closely monitored for fever at home. Patients who develop a temperature greater than 101° F or a rapidly rising temperature should contact their pediatrician immediately. Rectal temperatures should never be taken when patients are neutropenic.