Burns, cuts and knocks or bangs in our body are all part of life. Have you ever asked yourself how our metabolism can sustain so many different types of injuries? Well, all of these aggressions commence an orderly set of events that are involved in the healing response, in which the normal functional tissue (skin) is replaced by connective tissue (scar). The healing response is also characterized by the movement of specialized cells into the injury site.

The restoration of anatomical continuity and function is the result of the complex and dynamic process of healing. 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 complex ability to replace that structure by replacing exactly what was there before the injury. Smaller forms of life, such as the salamander and crab, can regenerate tissue in this manner. Throughout the past million years, we have lost this ability and can only recover a limited amount of damaged 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 formation and scar remodeling. This is the typical response that most humans develop following an injury. The pathological response to tissue injury stand in sharp contrast to the normal repair response.

3. Excessive healing (fibrosis and contractures)

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

4. Deficient healing (chronic ulcers)

Deficient healing is the opposite of fibrosis; it exists when there is insufficient deposition of connective tissue matrix and the tissue is thinned to the point where it can fall apart. Chronic uncurable ulcers are examples of deficient healing.

The Skin's Natural Healing Process

Just as an injury occurs, several different cells are sent to the damaged site, and the complex healing process begins.

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 damaged tissues. This is followed by attraction and synthesis of fibroblasts and collagen deposition, and finally remodeling by collagen cross-linking and scar maturation. Despite this coordinated sequence of events leading to normal wound healing, abnormal responses leading to fibrosis or chronic ulcers may occur if any part of the healing sequence is altered.