The 4 Stages of Wound Healing

The biological process to heal a wound occurs in 4 distinct phases. These include hemostasis, inflammatory, proliferative, and remodeling. Although wounds heal in a linear fashion, a patient may move forward, backward, or overlap in the healing stages depending on a multitude of factors. A normal, healthy wound will heal in under a month. If the wound takes longer than a month to heal, it is considered a chronic wound and often needs intervention from a wound care specialist.  


Hemostasis is a medical term that means the stopping of blood flow. A biological cascade occurs when a blood vessel sustains an injury that causes a wound. The initial response is vaso-constriction. The blood vessel constricts to slow the flow of blood out of the body, allowing clotting factors to more easily form.


Within seconds platelets begin to adhere to the inner wall of the blood vessel, forming a temporary plug to slow and stop the flow of blood. A platelet plug lacks structural strength to maintain vessel closure, so second clotting factor known as fibrin is needed for reinforcement. Fibrin integrates with the platelet plug to form a more stable secondary plug, allowing the vessel to begin healing. 


The inflammatory stage of wound healing begins simultaneously with the hemostatic phase, but extends much longer in the wound healing process. In a normal healthy wound the inflammatory phase can last up to 2 weeks. If it last longer than this, it is usually the sign of a  chronic wound. 

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The wound will often be red, warm, swelling, and painful during this phase. A special group of proteins known as cytokines begin to infiltrate the wound. Their job is to signal the body which growth factors and immune cells are needed to begin the healing process. The word inflammatory sounds alarming, but it is important for patients to  remember that it is a natural part of the wound healing process. 


Proliferation of new tissue is the hallmark of the proliferative phase of wound healing. This is a positive, optimistic time for patients dealing with a non-healing wound. The light at the end of the tunnel is near! New blood vessels are formed in a process known as neo-vascularization. 

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These vessels allow the previously wounded area to receive the vital nutrients and oxygen necessary  for healing the wound.  Re-epithelialization, or new skin formation, occurs, allowing the wound to contract and become smaller. The wound appears a healthy pinkish-red color. Eventually the surface of the wound is covered with a layer of new skin an is closed.


The wound is now healed, being completely covered with a layer of new skin. The body, however, still has work to complete. The new skin is still weak compared to skin that has not suffered from a wound, and must be protected. Collagen networks continue to strengthen, restoring the structure and function of healthy skin. This process can take up to a year to complete. Even so, it will only regain 80% of its previous strength. 

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Posted on in Wound Care Education.