Suggestion: Hello, common causes of leukopenia are medications, viral infections, and immune system disorders. When there is a decrease in white blood cells, if there are abnormal changes in the other two types of cells in the blood, i.e., red blood cells and platelets, the problem is more complicated, first of all, we should further examine, the most commonly done is a bone marrow examination to rule out the presence of other blood diseases. Low white blood cells can lead to low body resistance.