一般原因是：
A low white blood cell count usually is caused by one of the following:
- Viral infections that temporarily disrupt bone marrow function 病毒感染暫時影響骨髓造血機能
- Congenital disorders characterized by diminished bone marrow function先天性骨髓功能異常
- Cancer or other diseases that damage bone marrow 癌症或其他疾病損傷了骨髓
- Autoimmune disorders that destroy white blood cells or bone marrow cells自體免疫性疾病攻擊白血球或骨髓
- Overwhelming infections that use up white blood cells faster than they can be produced大規模感染大量消耗白血球
- Drugs that destroy white blood cells or damage bone marrow藥物殺傷白血球或損傷骨髓
Specific causes of low white blood cell count include:特殊原因有
- Aplastic anemia 先天再生障礙貧血
- Certain medications, such as antibiotics and diuretics 某些藥物的影響，例如抗生素和利尿劑
- Chemotherapy化療
- HIV/AIDS艾滋病毒感染
- Hypersplenism, a premature destruction of blood cells by the spleen脾功能亢進
- Infectious diseases細菌感染
- Kostmann's syndrome, a congenital disorder involving low neutrophil production先天性中性粒細胞減少症
- Leukemia白血病
- Lupus紅斑狼瘡
- Malnutrition營養不良
- Myelodysplastic syndromes 骨髓增生異常綜合症
- Myelokathexis, a congenital disorder involving failure of neutrophils to enter the bloodstream 先天性骨髓粒細胞減少症
- Other autoimmune disorders 其他自體免疫異常
- Other congenital disorders 其他先天性疾病
- Parasitic diseases 寄生蟲病
- Radiation therapy 放療
- Vitamin deficiencies 維生素缺乏
