Fatigue is a common symptom associated with having a low red blood cell count, according to the Aplastic Anemia and MDS International Foundation (AAMDS), but it is not a common symptom of a low white blood cell count. According to the AAMDS, some symptoms associated with a low count of white blood cells include mouth sores, skin infections, repeated infections and fevers, skin infections and bladder infections.
There are numerous reasons why someone would have a low white blood cell count, including vitamin deficiencies, HIV or AIDS, leukemia, infectious diseases, aplastic anemia, lupus or malnutrition, according to MayoClinic. Certain medications or having repeated infections in the body can also cause a low white blood cell count. Having lab tests analyzed by a doctor and discussing the cause of the lower white blood count cells are necessary steps for proper treatment.