How Does a Scab Form?
If you accidentally cut your finger, blood flows into the wound from tiny blood vessels in your skin. But your finger doesn’t bleed for long. When blood is exposed to air, it thickens, or clots. It plugs up the cut so that you do not lose too much blood.
Little by little, the clot hardens until it forms a hard crust or scab. Scab is usually dark red or brown in color. The scab provides a protective covering while the wound is healing. It also keeps out harmful germs that might cause infections.
Under the scab, new skin tissue grows and repairs the cut. Damaged blood vessels are fixed. White blood cells get rid of any dead blood and skin cells that may still be hanging around the cut.
By the time it’s all done, a new layer of skin is made. When the wound is healed, the scab falls off revealing new skin underneath. This usually happens by itself after a week or two.