Like most deficiency. If you dont have enough of something, its because you either don't make it, you lose it or you hide it. Neutropenia is no different. As examples, marrow failure or infiltration (not making them), autoimmune neutropenia (losing them), margination (hiding them), can all cause neutropenia. There are many other causes that fit into one of these categories. Treatment ranges from none to transplant.
Neutropenia Rx. Treatment of neutropenia depends on what's causing the condition to begin with. Some people have low white cells due to a medication they are taking. Others are born with it. Others develop it because of dangerous conditions such as leukemia. Please consult with a hematologist to determine what form of treatment is appropriate for you.