Diabetic Foot Ulcer

Definition 
A diabetic foot ulcer (DFU) is a chronic, non-healing wound that develops in individuals with diabetes. It typically occurs on pressure-bearing areas such as the heel, metatarsal heads, or hallux, and carries a high risk of infection and amputation.

Pathophysiology 
• The development of DFUs can be explained by four interconnected mechanisms: neuropathy, ischemia, infection, and impaired wound healing. 
• Neuropathy is the most common factor. Sensory neuropathy reduces pain perception, so minor trauma often goes unnoticed. Motor neuropathy alters foot structure, leading to deformities that concentrate pressure at specific sites. Autonomic neuropathy decreases sweat production, causing dry, cracked skin that is more prone to breakdown. 
• Ischemia, associated with peripheral arterial disease and microvascular dysfunction, restricts blood supply to the lower extremities. In addition, glycosylated hemoglobin reduces oxygen release. The resulting hypoxia suppresses angiogenesis and cellular repair, prolonging wound persistence. 
• Infection occurs readily once the skin barrier is breached. Poor circulation limits the delivery of immune cells, while bacteria thrive in ischemic tissue. Persistent infection accelerates tissue destruction and increases the risk of deeper complications, such as osteomyelitis. 
• Impaired wound healing reflects the systemic effects of hyperglycemia. Neutrophils show reduced chemotaxis and phagocytosis. Macrophages remain in a prolonged inflammatory state. Fibroblasts synthesize less collagen, and keratinocyte migration is impaired. These defects prevent wounds from progressing through the normal healing cascade. 
• Together, these mechanisms keep the ulcer in a chronic inflammatory state, making it difficult to heal and prone to recurrence and severe complications.