A wound that does not heal completely and in an orderly progression of steps and in a certain amount of time, is deemed chronic. These wounds may never heal and may remain in an inflammatory phase for a long time. Poor circulation plays a role, as does neuropathy and difficulty in moving, age, illness and trauma. When the immune system is not functioning optimally, this can contribute to a wound that does not heal properly. The inflammatory phase causes redness, swelling, pain and loss of function. Coagulation should occur releasing factor VII. This causes fibrin to plug the wound and allows platelets to attach to the fibers causing a scab to form. Next, leuckocytes are attracted and white blood cells are produced. This helps fight any infections at the wound site. Eventually, macrophages arrive aiding in debriding the wound and producing substances that aid in endothelial cell replication. Later on, the clot degrades and ground substance, collagen and capillaries are deposited. Eventually, new collagen is deposited and is replaced by normal skin. This process occurs in stages over a period of weeks but it doesn't occur properly in patients with chronic wounds.
Acute wounds are new wounds that are in the first phase of the healing process. It can be considered chronic if the injury does not heal within the normal amount of time it would take for the average person to recover from it or because," of poor blood supply, oxygen, nutrients or hygiene."