You scrape your elbow on the sidewalk, and it stings. Platelets are tiny parts of blood. They gather at an injury and help form a clot. The clot works like a natural bandage for your skin.

A scab is a dried clot. It forms within seconds or minutes after the skin is hurt. That is very fast. Your body starts to fix the scrape right away, before you even find a bandage.

A scab is also like a little shield. It helps keep germs out of the cut. The shield sits on top of the hurt skin and guards it while the body gets to work underneath.

Wash your hands first. Then wash the cut with mild soap and water soon after it happens. That helps stop infection. Always tell a grown-up when you get a cut, so they can help you take care of it.

Some cuts need more care than others. Deep, large or dirty cuts need more care than small clean ones, and a doctor may need to look at them. Small cuts heal faster than big, deep ones.

While a cut heals, keep it clean and covered with a bandage. A bandage covers a small cut to keep it clean while it heals. Even small cuts and scrapes need to be cleaned and covered so they do not get infected. Most minor cuts are healed in a week or less.

Under the scab, new skin is growing, and when the skin underneath has healed, the scab falls off by itself.

The scab can itch, but scratching it can break the new skin, and picking a scab makes a cut heal more slowly.

Look out for signs of infection. Yellow or green pus under or around a scab is one sign. Spreading redness, more pain or swelling are others. A grown-up should call a doctor.

A scar is a mark that is left on the skin after a wound has healed, and most scars fade as time goes by.

Words to know

• platelets: tiny blood parts
• clot: a blood plug
• scab: a crust
• infection: a germ problem
• scar: a leftover mark