What causes leukopenia (reduced white blood cells)?

There are several causes of leukopenia (reduced white blood cell count), mainly including the following: 1. **Bone marrow-related causes**: Conditions such as aplastic anemia, acute leukemia, and myelodysplastic syndromes can impair normal bone marrow function, leading to decreased production of white blood cells. 2. **Infectious factors**: Particularly viral infections such as chickenpox (varicella), viral hepatitis, and rubella can lead to excessive destruction or consumption of neutrophils, thereby reducing the white blood cell count. 3. **Medication effects**: Certain antithyroid drugs, chemicals such as chloramphenicol, as well as chemotherapy and radiotherapy, may suppress bone marrow function, resulting in leukopenia. 4. **Immune system abnormalities**: Autoimmune diseases such as systemic lupus erythematosus (SLE), dermatomyositis, and rheumatoid arthritis, as well as immune system dysregulation, can also lead to a decrease in white blood cells. 5. **Other factors**: These include malnutrition, particularly deficiencies in vitamin B12 and folic acid, as well as certain hereditary disorders and hyperfunction of the spleen. Please note that the above list includes only some of the possible causes of leukopenia. The exact cause should be determined based on individual clinical presentation and medical evaluation.