What are Stretch Marks?

The elastin in skin is capable of being damaged to the point where it cannot be repaired. Typically when a person is younger and skin is healthy the elastin can be constantly renewed through the typical processes the body goes through to repair itself. New elastin is made and damaged elastin is replaced.

This elastin is what helps skin to "pop back" into place after being stretched. Damage to the elastin can bring about a host of problems, including stretch marks.

Elastin can be compared to a very tiny fishnet or crisscross of rubber bands that are only visible on a microscopic level. When elastin is damaged, torn, or just worn out the skin becomes scarred in what we call a stretch mark.

It's interesting that while stretch marks are visible to the eyes they virtually disappear under a microscope. The skin itself is not damaged in the area of a stretch mark but the elastin is.

This is why stretch marks are not painful the way other blemishes in the skin can be. A rash or eczema can hurt to the touch because the nerve endings in the cells of the skin have been damaged and are sensitive or sore to the touch. But stretch marks are damage to the elastin only and not the skin cells.

The skin can repair many of its own components including collagen and the cells of the skin. When we shed skin cells we aren't usually left with any marks or scars; even the red mark caused by a cut or scratching goes away after a few minutes or hours as the skin replaces those cells with new ones. Collagen is made new and is also replaced. But elastin is not that easily replaceable so you can easily have stretch marks.

This explains why stretch marks do not heal over time the way other scars may. The part of the skin that's damaged just doesn't get renewed. Typically anything that causes deep damage to the skin will leave scars - a small scrape or cut will heal up without a mark, but acne, which occurs deep in the sub-layers of the skin, can leave scars. The same is true of those deep incisions needed for surgery or due to accidents. The damage is deeper so they don't heal as easily. Stretch marks, which affect the elastin, just don't go away.

What causes stretch marks?

As with many problems of the human body, doctors and biologists don't always completely agree with what causes stretch marks.

It seems like an obvious answer that stretch marks are caused by the skin being stretched too far or so much that it's unnatural. This would explain why pregnancy and being overweight causes stretch marks when most people of a normal size and weight don't have them.

But not everyone that's overweight or that has been pregnant gets stretch marks. It's not as if these things automatically cause damage to the skin and to the elastin so that stretch marks will just happen.

Hormones and stretch marks.

Some doctors believe that it is a change in the hormones that regulate the skin's health that actually cause or prevent stretch marks. When a person is putting on weight, when they are lifting weights during bodybuilding exercises, or when they are pregnant the body goes through a host of hormonal changes. The metabolism of the body and of the skin are thought by some to be responsible for stretch marks or the lack thereof.

Stretching and stretch marks.

The skin stretches constantly as we've already covered. Those who are physically active are stretching their skin more than any average or normal person. Someone that practice yoga or that plays professional sports will stretch their skin to its maximum capacity.

One theory regarding stretching and stretch marks is that it's not the stretching itself but when skin is stretched past a natural stage and then is held there for any length of time.

Imagine doing this to a rubber band - stretching it out and then holding it there for hours or days. Obviously the elastic would get worn out and the band wouldn't snap back the way it should.

The difference between damage to a rubber band and damage to the skin is that skin is a living, breathing organ that gets scarred when it gets damaged. Acne leaves a scar on the skin, as do incisions and deep cuts. These things may heal to a certain extent but that damage, once it's done, leaves a mark on the skin that's difficult to undo.

Dry skin and stretch marks.

Does dry skin cause stretch marks or make you more prone to them? There is some debate over this issue as well. No doubt one reason that people believe this is the skincare manufacturers that advertise cocoa butter and other lotions and moisturizers as a fix or preventative measure for stretch marks.

Having dry skin can cause or contribute to many problems with the skin. When the skin is dry it's less able to bounce back after being stretched or folded such as when you make facial expressions. Those with very dry skin are more prone to lines and wrinkles whereas those with oilier skin or who hydrate themselves have fewer problems in this area.

It seems that dry skin may contribute to stretch marks simply because the skin is not as healthy as it can be when it's dry and because it doesn't renew and repair itself as easily. Any cuts or damage to the skin is not as easily healed when it's dry. This may be true as well of the damage to the elastin that results in stretch marks - the body just cannot heal these as easily as it can anything else when it doesn't have the adequate moisture needed to keep itself in good repair.

Inflammation of the skin is also part of why we get stretch marks and of course dry skin means inflamed and irritated skin. Water and hydration are healing agents for the skin and help to keep down inflammation from things like rashes or irritants and pollutants in the air. This too may be a reason why dry skin at least contributes to stretch marks.