Persons with diabetes are generally more prone to infections than non-diabetic people.

Due to deficiencies in the ability of white blood cells to defend against invading bacteria, diabetics have more difficulty in dealing with and mounting an immune response to the infection.
Infections often worsen and may go undetected, especially in the presence of diabetic neuropathy or vascular disease.

Often, the only sign of a developing infection is unexplained high blood sugar, even without fever.

The combination of fever and high blood sugar often warns of a severe infection requiring hospitalization. Lesser degrees of infection are often treated on an outpatient basis.