When we are small, we usually have to endure many different types of injuries such as burns, cuts, and knocks or bangs in our body. These injuries become less during adulthood, but we still sustain them well. How is it possible? Well, all of these aggressions initiate an orderly set of steps that are involved in the healing response, in which the normal healthy tissue (skin) is replaced by connective tissue (scar). The healing response is also characterized by the movement of specialized cells into the wound site.

Healing is the complex and dynamic process that results in the restoration of anatomical continuity and function. Following an injury, your body can respond in 4 different ways:

1.Regeneration (exact replacement)

Skin regeneration occurs when there is loss of structure and functionality. The beauty of our organism is that it has the sophisticated ability to replace that structure by replacing exactly what was there before the damage. Lower forms of life, such as the salamander and crab, can regenerate tissue in this way. As man has evolved, we have lost this ability and can only recover a limited amount of injured tissues by the process of regeneration.

2. Normal repair (reestablished equilibrium)

Normal repair is the response where there is a re-established equilibrium between scar creation and scar remodeling. Most humans experience this type of response following an injury. The pathological response to tissue damage stand in sharp contrast to the normal repair response.

3. Excessive healing (fibrosis and contractures)

In excessive healing there is an exaggerated deposition of connective tissue that results in altered structure and, thus, loss of functionality. Fibrosis, structures, adhesions and contractures are examples of excessive healing. Keloids and hypertrophic scars in the skin are examples of fibrosis. Contraction is part of the normal process of healing but if excessive, it becomes pathologic and is known as a contracture.

4. Deficient healing (chronic ulcers)

Deficient healing is the opposite of fibrosis; it appears when there is an abnormally low deposition of connective tissue matrix and the tissue is thinned to the point where it can fall apart. Persistent uncurable ulcers are examples of deficient healing.

The Skin's Natural Regenerative Process

When an injury occurs, a movement of different cells comes immediately and the complex healing process just begins in the moment it's happened.

The normal healing cascade begins with an coordinated process of hemostasis and fibrin deposition, which leads to an inflammatory cell cascade, characterized by neutrophils, macrophages and lymphocytes within the tissue. This is followed by migration and proliferation of fibroblasts and collagen deposition, and finally remodeling by collagen cross-linking and scar maturation. Despite this coordinated sequence of steps responsible for normal wound repairing, pathologic responses leading to fibrosis or chronic ulcers may occur if any part of the healing cascade is altered.