Page 2

Normal skin has two layers. The epidermis is a thin, outer layer of cells that protect from outside chemicals and objects. This layer is meant to take punishment and can recover from most of the damage it takes. Below the epidermis lies the thick, deep dermis, made primarily out of protein filaments called collage. Like wet cotton batting in a pillow, it gives skin both firmness and pliability. Buried in this collagen, you’ll find sweat glands, hair roots, blood vessels, nerves, and the motile fibroblast cells that spin the collagen.

Scars form when fibroblasts overreact to damage to the dermis. Instead of calmly waiting for a new network of intricately knit collagen filaments and epidermal cells to grow, the fibroblasts firehose in a super-dense mix of collagen that cements the wound closed. This collagen is so thick that no hair roots, sweat glands, and very few nerves can grow into it.

This quick fix works fine for nicks and cuts. It’s even an evolutionary advantage because it gives padding to an area that takes a lot of superficial damage, like knees that are constantly getting scraped. In a third-degree burn, where large areas are deeply destroyed, the body will try to replace the whole section with scar tissue. Instead of forming padding, it replaces a whole depth of damaged skin. All the functionality of skin--the ability to sweat, feel and regulate body temperature--is lost to this inflexible mass. To compound matters, the dense collagen shrinks as it heals, puling the surrounding skin. If this was allowed to happen in an area like Lisa’s hands, they would be frozen into a claw shape.

Typically, surgeons prevent these complications by artificially filling in the damaged skin with a substitute, says Dr. Stephen King, the medical director at the Wound Care Center in Memphis. The most popular substitute is a skin graft taken from the patient, usually from the inner thigh. The graft is the epidermis and enough of the dermis to keep the epidermis alive for a little while.