Pediatric Neutropenia: Low White Blood Cell Count in Babies and Children

Within the first year or two of life, your child may have a routine blood test that could reveal a condition known as pediatric neutropenia, which means your child has a deficiency of neutrophils, white blood cells that fight bacteria.

While the words "deficiency" and "blood cells" often call to mind anemia, that's a different blood disorder. Anemia is related to low red blood cells or low hemoglobin. In a 1-year-old, as in an adult, these disorders can be related to low iron levels.

The most common reason for pediatric neutropenia is a viral infection since the body uses up white blood cells to fight the infection. This is a temporary condition. White blood cell levels should return to normal once the child recovers.

However, a low white blood cell count in babies may be caused by an autoimmune condition, pediatric neutropenia. Autoimmune neutropenia is often diagnosed around 7 to 9 months of age, and fortunately, it disappears in most children on its own within two years.

Prevalence

Rates of neutropenia vary based on a child's ethnicity and where they live in the world. Globally, the condition is most prevalent among children in North Africa and Arab nations, affecting about 15.4% of children under 6 years of age. Neutropenia is more common in infancy and early childhood with rates dropping as a child grows.

In the United States, the rate of neutropenia is 7.2% for children under 2 years old and 3.7% for those aged 3 to 5. It drops to 2.3% for 6 to 8-year-olds.

Overview

Pediatric autoimmune neutropenia may also be called chronic benign neutropenia of childhood. This condition is similar to immune thrombocytopenia (ITP) and autoimmune hemolytic anemia (AIHA). 

Despite the fact that the bone marrow makes the neutrophils normally, the body incorrectly makes antibodies to neutrophils that mark them for destruction, leading to neutropenia.

Symptoms

Most children with autoimmune neutropenia have no symptoms. That is because, despite the exceptionally low neutrophil count, serious infections are rare.

The neutropenia may be discovered on a CBC draw secondary to an ear or respiratory infection. Some children might experience mouth sores or skin infections.

Diagnosis

As with other forms of neutropenia, the first diagnostic test is a complete blood count (CBC). The absolute neutrophil count (ANC) is typically below 1000 cells per microliter and can be below 500. Usually, the hemoglobin and platelet count are normal.

A peripheral blood smear, an examination of the blood cells under a microscope, may also be drawn. Although the number of neutrophils is low, they have a normal appearance.

Next, your physician will likely obtain CBCs twice weekly for at least 6 weeks to ensure that your child does not have cyclic neutropenia (a condition where the neutrophils are only low for a couple of days every 21 days).

In some patients, anti-neutrophil antibodies are never identified. In these cases, if the age and presentation fit the picture of autoimmune neutropenia, the diagnosis is presumed.

In rare cases, a bone marrow examination might be necessary to rule out other causes of neutropenia. This typically occurs in children whose presentation and infections don't fit the typical picture of pediatric autoimmune neutropenia.

Treatment

There is no specific treatment for autoimmune neutropenia of childhood. The anti-neutrophil antibodies will spontaneously disappear and the neutrophil count will return to normal. Spontaneous recovery occurs by 5 years of age, with neutropenia lasting on average 20 months.

If he develops a fever, your child will typically undergo a CBC, blood culture (placing blood in glass bottles to look for bacteria), and at least one dose of antibiotics. If the ANC is less than 500 cells/mL, your child will likely be admitted to the hospital on IV antibiotics for observation.

If your child looks well and the ANC is greater than 1,000 cell/mL, you will likely be discharged home for outpatient follow-up.

Medications used for other immune blood disorders (ITP, AIHA) like steroids and intravenous immune globulin (IVIG) are not as successful in autoimmune neutropenia. Sometimes filgrastim (G-CSF) can be used during active infections to stimulate the release of neutrophils from bone marrow to blood circulation.