Infection Risk

Diabetes creates conditions in which infection develops more easily and may be harder to detect. Persistent hyperglycemia interferes with neutrophil movement, phagocytosis, and cytokine signaling. The immune response becomes less efficient at finding organisms, containing them, and coordinating inflammation. High glucose also affects the tissues infection must move through. Peripheral arterial disease reduces oxygen delivery and slows healing. Neuropathy removes the warning system of pain and pressure, allowing a blister, crack, or foreign object in a shoe to become a wound before the patient notices it. Infection then worsens glucose control. Stress hormones increase hepatic glucose release and insulin resistance, so a patient whose glucose has been stable may develop persistent hyperglycemia during an infection. This feedback loop matters clinically: infection raises glucose, and elevated glucose makes infection harder to clear. People with diabetes have increased risk for respiratory infections, urinary tract infections, skin and soft-tissue infections, candidal infections, and foot infections. Influenza, pneumococcal disease, hepatitis B, and herpes zoster are also more common than in adults without diabetes.