Differential Diagnosis for Neutropenia in an 11-year-old Female

Single Most Likely Diagnosis

• Viral infection: Many viral infections can cause neutropenia, and given the age of the patient and the lack of other abnormalities on the CBC, a viral etiology is plausible. Common culprits include influenza, respiratory syncytial virus (RSV), and human immunodeficiency virus (HIV), although the latter would be less likely without other symptoms or risk factors.

Other Likely Diagnoses

• Medication-induced neutropenia: Various medications can cause neutropenia, including certain antibiotics, anticonvulsants, and nonsteroidal anti-inflammatory drugs (NSAIDs). The history of recent medication use is crucial in diagnosing this condition.
• Autoimmune neutropenia: This condition occurs when the immune system produces antibodies against neutrophils, leading to their destruction. It is more common in children and can be associated with other autoimmune diseases.
• Benign ethnic neutropenia: Some ethnic groups, particularly individuals of African descent, can have a lower neutrophil count without any underlying disease. This condition is benign and does not increase the risk of infections.

Do Not Miss Diagnoses

• Aplastic anemia: Although less common, aplastic anemia is a serious condition where the bone marrow fails to produce blood cells, including neutrophils. It can be caused by viral infections, medications, or exposure to toxins.
• Leukemia or lymphoma: These malignancies can present with neutropenia among other symptoms. Early detection is crucial for effective treatment.
• Severe combined immunodeficiency (SCID): A group of rare disorders caused by mutations in different genes involved in the development and function of the immune system. SCID can present with severe infections and neutropenia.

Rare Diagnoses

• Cyclic neutropenia: A rare genetic disorder characterized by periodic episodes of neutropenia, often associated with other cytopenias.
• Shwachman-Diamond syndrome: A rare genetic disorder that affects the bone marrow, pancreas, and skeleton, leading to neutropenia and other cytopenias.
• Glycogen storage disease type Ib: A rare genetic disorder that affects glycogen metabolism and can lead to neutropenia and neutrophil dysfunction.

Each of these diagnoses requires careful consideration of the patient's clinical presentation, medical history, and additional diagnostic tests to confirm the underlying cause of neutropenia.