Many factors can hamper the body's ability to heal wounds. Among the most common are:

• Diabetes
• Chronic infection
• Vascular disease and poor blood flow
• Radiation therapy
• Injury
• Poor nutrition
• Age
• Limited activity and movement
• Weight
• Hyperglycemia (high blood sugar)
• Smoking
• Certain medications

Among the most common hard-to-heal wounds are:

• Diabetic foot ulcers
• Pressure ulcers
• Leg ulcers
• Infection-related wounds
• Slow-to-heal surgical wounds
• Skin tears and grafts
• Trauma-related wounds

When a wound shows no signs of healing for two to three weeks, it is time for it to be examined to see if further treatment is necessary.