Why People Get Scabs

By Howard J. Bennett

Since I work with kids, I see scabs every day. Most of the time, they are small, crusty lumps on a child’s arm or leg. Occasionally, I see really big scabs that look like a slice of mangled pizza. Bike accidents and sliding across a hard surface in shorts are most likely to cause big scabs.

Although scabs look gross to most people, I think they are beautiful! That’s because I know the amazing things the body had to do to produce the scab. Basically, a scab is a bandage your body makes after it’s been injured. Scabs are made up of blood cells, platelets, and special chemicals from your circulatory system.

When blood travels through your arteries and veins, it has to stay in its “liquid” form so it can carry oxygen and nutrients to every part of your body. Since we need blood to survive, it’s logical that the body would have a system to keep this precious resource from escaping after an injury. The system is called coagulation—that’s doctor talk for clotting.

As soon as one of your blood vessels is cut, a complex process begins to stop the bleeding. First, platelets, which are like little disks in your blood, move to the damaged area to form a plug. At the same time, other parts of your blood form tough strands called fibrin that strengthen the platelet plug. Fibrin is like a microscopic mesh that is the backbone of the clot.

Once the bleeding has stopped, some of the clotted blood ends up on the surface of your skin as a scab. The scab will remain in place for a week or so until the skin under the scab is fully healed. At that point the scab will fall off—assuming you don’t pick it off before it’s ready thereby reopening the cut!

Of course, if you’ve ever had stitches, you know that the body’s ability to make clots isn’t perfect. If you get a deep cut or if you cut an artery, the injury will continue to bleed until it’s stitched together. Depending on the size and location of the cut, stitches will be removed in five to 14 days.

Bonus Fact: In some parts of the world, healers use solider ants to close wounds. The ant is positioned so that its big jaws are on either side of an open cut. The ant is then moved toward the cut. When the ant bites the victim—I mean patient—its jaws bring the cut tissue together. The healer then cuts off the ant’s head, which stays in place and acts like a stitch. The healer will use as many ants as necessary to close the wound.

© 2012 Howard J. Bennett. All Rights Reserved.
(First published in the Washington Post 1/11/10.)

For more KidsPost articles and lots of other cool stuff,
please visit Dr. B’s website at  www.howardjbennett.com.

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