Your body produces white blood cells (leukocytes), which help fight bacterial infections, viruses and fungi. If your child has too few or too many white blood cells, in general, here's what it means:

  • Low white blood cell count (leukopenia) means having too few leukocytes circulating in the blood. A long-term low white blood cell count increases the risk of infections and may be caused by a number of different diseases and conditions.
  • High white blood cell count (leukocytosis) means having too many leukocytes circulating in the blood, usually from having an infection. A number of different diseases and conditions may cause a long-term high white blood cell count.

There are several types of white blood cells, each with a different disease-fighting activity. The main types are:

  • Neutrophils
  • Lymphocytes
  • Monocytes
  • Eosinophils
  • Basophils

White blood cells disorders involving a specific type of white blood cell include:

  • Neutropenia. Neutropenia (noo-troe-PEE-nee-uh) is a low number of neutrophils, a type of white blood cell that fights infections of fungi and bacteria. Neutropenia can be caused by cancer or by diseases, disorders or infections that damage bone marrow. In addition, certain medications and other diseases or conditions can cause neutropenia.
  • Lymphocytopenia. Lymphocytopenia (lim-foe-sie-toe-PEE-nee-uh) is a decrease in lymphocytes, the type of white blood cell that, among other tasks, protects your body from viral infections. Lymphocytopenia can result from an inherited syndrome, be associated with certain diseases, or be a side effect from medications or other treatments.
  • Monocyte disorders. Monocytes help get rid of dead or damaged tissue and regulate your body's immune response. Infections, cancer, autoimmune diseases and other conditions can cause an increased number of monocytes. A decreased number can be the result of toxins, chemotherapy and other causes.
  • Eosinophilia. Eosinophilia (e-o-sin-o-FIL-e-uh) is a higher than normal number of eosinophil cells, a type of disease-fighting white blood cell. Eosinophilia can be caused by a variety of conditions and disorders, most commonly by an allergic reaction or a parasitic infection.
  • Basophilic disorders. Basophils account for only a small number of white blood cells, but they have a role in wound healing, infection and allergic reactions. A decreased number of basophils can result from high thyroid hormone levels, allergic reactions or infections. An increased number can be caused by certain types of blood cancer, low thyroid hormone levels or other disorders.
Jul. 09, 2014