In individuals with diabetes, nerve damage can lead to skin problems in the feet such as dryness, cracks, fissures, and calluses. These conditions increase the risk of infection, and once an infection develops, it can progress rapidly. As a result of infection, blood circulation in the feet can be adversely affected, making wound healing difficult and prolonged. The staging of diabetic foot ulcers by severity is as follows:

Stage 0: Healthy skin
Stage 1: Superficial ulcer
Stage 2: Deep ulcer (muscle or tendon involvement)
Stage 3: Ulcer with bone involvement
Stage 4: Forefoot or toe gangrene (limited gangrene)
Stage 5: Foot gangrene (extensive gangrene)