Neutropenia occurs when a person has a low count of white blood cells called "neutrophils," which are responsible for fighting off bacterial and other infections. The condition occurs when the neutrophil count drops below 1700 cells per microliter, and severe neutropenia occurs at levels below 500, according to Mayo Clinic.
The causes of neutropenia include autoimmune disorders, cancer and bone marrow disorders. Excessive use of drugs or alcohol is also a possible cause, according to Mayo Clinic.
Because neutropenia itself does not cause symptoms, individuals may find out they have the condition either during a routine blood test or if they experience the symptoms of a severe infection. Along with the typical symptoms, they may have rashes, abscesses, or unhealing wounds and ulcers, states WebMD.