Diabetes mellitus is a heterogeneous metabolic disorder characterized by hyperglycemia due to defects in insulin secretion, insulin action, or both. Chronic hyperglycemia over a long period of time causes disturbances in carbohydrate, protein, and lipid metabolism, and damages various organs, especially the heart and blood vessels, kidneys, eyes, and nerves.

People with diabetes are at higher risk of body infections than normal people. To avoid the disease from getting worse, recognizing the signs of infection due to diabetes plays a very important role.