Neutropenia
Neutropenia is a condition in which the blood has an abnormally low number of neutrophils, a type of white blood cell that plays a critical role in defending the body against bacterial and fungal infections.
It can be caused by bone marrow disorders, chemotherapy, certain medications, viral infections and autoimmune conditions. In some cases, particularly in people of African and Middle Eastern descent, a lower neutrophil count can be a normal variant (benign ethnic neutropenia).
People with significant neutropenia are at increased risk of infections, which can become serious quickly. Signs of infection to watch for include fever, sore throat, mouth ulcers and skin infections.
Neutrophil count is measured as part of a full blood count. If persistently low, further investigation may be needed to identify the underlying cause.
Causes of Neutropenia
Neutropenia results from decreased production, increased destruction, or margination (redistribution) of neutrophils.
Common causes include:
- Chemotherapy and radiotherapy, the most frequent cause of severe neutropenia
- Medications such as carbimazole, clozapine, sulfasalazine and some antibiotics
- Viral infections including influenza, HIV, hepatitis and Epstein-Barr virus
- Bone marrow disorders such as myelodysplastic syndromes and aplastic anaemia
- Autoimmune neutropenia, in which the immune system attacks neutrophils
- Nutritional deficiencies of vitamin B12, folate or copper
Benign ethnic neutropenia is a normal variant seen in people of African, Middle Eastern and some Caribbean backgrounds, where baseline neutrophil counts are lower without any associated health risk.
Tests that can help check this condition
Learn more on the official NHS page .
Medical review
Dr. Shahzaib Ahmad MBBS, BSc, MRCP, FRCA, FFICM
Clinical Supervisor - Vitall|GMC 7495062|Profile
Reviewed on 22/05/2026
Next review due 22/05/2027
Review focus: Blood biomarkers, laboratory testing methodology, and biochemical interpretation.
