The function of white blood cells in the body is to fight infection. There are several different types of white blood cells that have different 'jobs' in the process of fighting viruses, bacteria and fungi that can infect the body. Your level of risk when your white cell count drops depends on how low the count drops, how long it stays low and which types of white cells have dropped.
Bacterial Infections
One of the primary risks and dangers of a low white blood cell count is infection. Because these cells are responsible for fighting disease, people with low white blood cell counts are at higher risk for developing infections. Common symptoms, such as redness, swelling, pus formation, cough or nasal drainage, may not be present so people with low white cell counts must be very alert to any changes in their condition. The most common source of infection in these people is bacteria normally found on the skin.
Fungal Infection
Fungal infections are also common in people with low white blood cell counts. They are most commonly found in the mouth, lungs, genital area, and skin. Fungi are primitive vegetables, such as mushrooms or mold, and are hard to kill. They live in the air and soil, on plants and in the water. Some fungi live in or on the human body and only half are harmful. However, with low white blood cells counts, an overgrowth of fungus is possible.
Viral Infection
When a virus enters the body, it triggers the immune system. According to the Merck Manual, the first level of defense is the white blood cells, which have learned to identify, attack and destroy the virus. After recovery, the white blood cells have memory of the attack and are able to respond more effectively the next time. Without the white blood cells, even a minor virus can result in death.
Sepsis
Sepsis is an overwhelming infection that has migrated to the blood stream. It usually is caused by a bacterium. According to the National Library of Medicine, sepsis can be life threatening, especially in people who have a reduced white cell count or compromised immune system. Physicians diagnose sepsis with a blood test or blood culture. However, in people who are already on antibiotics this test may show a false negative. Treatment is immediate and often initiated in an intensive care unit. The mortality rate for people who develop sepsis and already have low white blood cell counts is as high as 60 percent.
