The medical term “localized disease” refers to a condition that is confined to one organ or system of the body. For example, an ear infection is a localized disease because it typically only affects the “middle ear” just behind the eardrum. While ear infections can spread to other parts of the body, this is very uncommon. A “systemic disease”, on the other hand, is one that has systemic manifestations. For example, diabetes is a disease that affects the level of glucose in your blood. Since every organ in the body is reliant on this blood, diabetes can have many systemic effects ranging from cardiovascular disease to nerve damage.