Why do we have scar tissue (e.g. burns, injuries, acne) that remain for the rest of our lives? Why aren’t the cells replaced by normal cells, gradually removing the scar? I’m 60, and I have some acne scars that are 40-something years old. Why haven’t they disappeared?
The underlying collagen ‘scaffolding’ on which the skin cells are layered is altered permanently, and because the collagen structure doesn’t change over time the scar won’t disappear.
In short, the way the body repairs itself is vastly different than the way it formed initially.
I’ll let others answer the why of it. But it does really suck, I got a really bad cut just below my lower lip (between the lip and chin) and will have that scar for life.
Does it depend on the age at which the injury occurred, and the type of injury? When I was around 6-7, I burned my hand reaching into a hot oven, and had a scar for many years, definitely into my teens and twenties. Then it just gradually disappeared, and there hasn’t been any trace of it for a long time. Why did that scar eventually disappear, unlike my acne scars? And come to think of it, I still have a few chicken-pox scars that I acquired **before **the burn on my hand.
Scar tissue can be surgically removed and the incision glued back together with a thin line where the scar was.
Had there been surgical glue at the time of the original incision/cut the scar could have been minimized then and faded to insignifigance by now.
Sorry, oftentimes it’s not nearly that simple. I don’t know how much original trauma repair work or later scar revision work you’ve done, spingears, but I’ve done my share and depending on the mechanism of injury, underlying tissue damage, amount of lost tissue, and a host of other factors, even the best surgeon can’t repair some wounds without a lot of scarring. Oftentimes, later revisions can be done to minimize the scar’s appearance and debulk the fibrous scar tissue, but that generally needs careful work by a good reconstructive surgeon.
And surgical glue is nice and fine and all that (I sure use it often enough) but it’s not a miracle cure or anything. A nice subcuticular suture can give equivalent approximation of wound edges, with a whole lot of re-inforcement of underlying tissue, and result in less scarring than with glue. Your assertion that use of glue will result in insignificant scars is flat-out wrong. Glue is a nice, handy tool to use on certain types of lesser lacerations and tends to give good results on small wounds that wouldn’t have tended to scar much in the first place.
As to the OP, well, scars are made from fibroblasts, a connective tissue that is the body’s response to significant tissue damage. As connective tissue, it seems to be designed to last for a lifetime.
If wounds are cleansed, trimmed of dead tissue, and carefully repaired, then less scar tissue is formed in the first place. But some people just form a lot too, even when maximum precautions are taken. Google “keloid” images sometime and see what happens when the scar process runs amok.
I must disagree with ** Qadgop ** medical advice. Your good mental health requires that you don’t google “keloid” images.
I severely lacerated my left hand on a broken bottle when I was 6. My father is a physician, and he had a colleague (some kind of specialist) at the hospital do the surgery on my hand. I still have the scar. It’s grown with my hand, and is now about 2 inches long. It has faded somewhat with time (over 30 years now), but is still pretty evident.
Droll Qadgop, very droll. 
Thank you Qadgop.
Sometimes when I autopsy someone there’ll be a missing appendix, but no scar. Often it turns out that that person had an appendectomy in early childhood and the scar gradually faded until I can’t find it. Skin in youth does a better job of remodelling than older skin.
The kicker? If I take a place where there isn’t a “scar” and put the skin under the microscope, guess what. There is a scar (or at least an increased density of collagen). So the fact that you can’t see a scar with the naked eye doesn’t mean it isn’t there.
Scar tissue gradually remodels over a year or even years, but never reaches the tensile strength of original skin.
Thanks for the comments everyone.
I’ve often wondered about my son’s big scar.
He had a PDA ligation at about 25- 26 weeks gestation of age (he was about 1 or 2 weeks old at the time). The scar is between some ribs from his back to under his arm. The scar was about one to two inches at the time and it grows with him as he grows. I’d say it’s about 7 inches now.
Having seen the amazing speed at which small babies often heal from small injuries so quickly, I often wondered why this scar didn’t stay small, or more precisely, why it “grows up” with him.
He likes the scar and thinks it’s “manly”. He’s 8 and kinda interested in “manly” things right now.
Realized I forgot to note that this happened when I was about 3.
I was reading a book about scurvy this month, how long it took them, what sorts of ‘experiments’ were done, all the theories, etc.
Seems it was pretty scary - apparently one of the side-effects of lack of ascorbic acid (vitamin C) is that old wounds would re-appear and open up, and broken bones would part again. :eek:
So even though it looks ‘healed’, I can understand that there’s something different about the areas in question.