Your blood is made up different types of blood cells, including white blood cells, or leukocytes. White blood cells are an important part of your immune system, helping your body to fight off diseases and infections. If you have too few white blood cells, you have a condition known as leukopenia. There are several different types of leukopenia, depending on which type of white blood cell your blood is low in. Each type protects your body from different kinds of infections. If your blood is low in neutrophils, you have a type of leukopenia known as neutropenia. Neutrophils are the white blood cells that protect you from fungal and bacterial infections. Leukopenia is so often caused from a decrease in neutrophils that some people use the terms “leukopenia” and “neutropenia” interchangeably. Another common type of leukopenia is lymphocytopenia, which is when you have too few lymphocytes. Lymphocytes are the white blood cells that protect you from viral infections.
White blood cells are manufactured in bone marrow — the spongy tissue inside some of your larger bones. A low white blood cell count usually is caused by:
- Viral infections that temporarily disrupt the work of bone marrow
- Certain disorders present at birth (congenital) that involve diminished bone marrow function
- Cancer (or other diseases that damage bone marrow)
- Autoimmune disorders that destroy white blood cells or bone marrow cells
- Severe infections that use up white blood cells faster than they can be produced
- Medications, such as antibiotics, that destroy white blood cells
When to see a doctor
A low white blood cell count is usually found when your doctor orders tests for a condition you're already experiencing. It's rarely an unexpected finding or simply discovered by chance. Talk to your doctor about what your test results mean. A low white blood cell count, along with results from other tests, might already indicate the cause of your illness. Or your doctor may suggest other tests to further check your condition.
Because a chronic very low white blood cell count makes you vulnerable to infections, ask your doctor about precautions to avoid catching contagious diseases. Always wash your hands regularly and thoroughly. You might also be advised to wear a face mask and avoid anyone with a cold or other illness.
Having a low white blood cell count can help point your doctor to the cause of your illness. Usually, your doctor will learn that your white blood cell counts are low after ordering a blood test like a complete blood count to check on a different condition. Anyone who has a condition that can cause leukopenia is at risk. Leukopenia usually doesn’t lead to noticeable symptoms. So your doctor will monitor your blood cell counts carefully if you have any of the conditions that can lead to it. This means undergoing frequent blood tests.
Treatment for leukopenia depends on which type of white blood cell is low and what’s causing it. You may need other treatments to take care of any infections that develop from not having enough white blood cells. Medications can be used to stimulate your body to make more blood cells. Or you may be prescribed medications to clear up the cause of the reduced cell count, such as antifungals to treat fungal infections or antibiotics to treat bacterial infections.