Scar Healing Phases
By Brian Kobienia, MD, FACS on January 19, 2013
Scars go through many phases of healing. The length of time of each of these phases is dependent on many factors. The age and thickness of the skin tends to be a factor that influences the remodeling phase of scar healing.
The first phase of scar healing is hemostasis or coagulation. After surgery or injury the body has to stop any bleeding. Certain cells such as platelets are deposited in the wound to stop the leakage of blood. This starts a cascade effect of other cells and factors that are used to initiate scar formation.
The next phase of scar healing is inflammation. Cells that are attracted to the area by chemicals release by cells in the first phase of scar healing are now responsible for removing any foreign materials such as debris or bacteria in the wound. The type of wound typically dictates the length of this phase of healing. In other words, an abrasion with a broad surface area will tend to have a longer inflammatory phase than a clean surgical incision. The dirtier the wound the longer the inflammatory phase in general.
During the proliferation phase of scar healing cells such as fibroblast are creating collagen and blood vessels are being formed in the process called angiogenesis. Sometimes when scar formation goes awry this phase is prolonged indefinitely. A keloidal scar is a process where the proliferation phase of scar formation progresses unchecked. This creates a scar that exceeds the border of the injury. A hypertrophic scar, on the other hand, has a definite endpoint to the laying down of extra collagen but does prolong the phase of proliferation beyond what would be considered normal.
Remodeling is the final phase of scar formation. This is the process where the scars contract due to myofibroblasts. Extra collagen is removed and the scar is typically thinned. The length of this process is often determined by the thickness of the skin which injury exists. In other words, eyelid skin heals and matures a scar much faster than skin on the back which is typically thicker.
This process is very fragile and complex. It is highly susceptible to interruptions and delays depending on the local environment. For example, wound healing in a diabetic is slower because of the poor blood supply often associated with the microvascular disease of diabetes. Infection is another reason why wound healing can be delayed. By controling the local environment scars can often proceed without interruption through all phases of scar maturation. This typically will give you the best chance of the optimal scar. Unfortunately, with every cut there will be a scar. Modern science has yet to advance to the point of making scars obsolete.
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