A scar is nature’s thread, mending broken or cut skin with a waterproof closure. A skin cut initiates a complex inflammatory process designed to manufacture that thread. Like a skilled army, specialized cells lay down a clot to stop the bleeding, while wound-healing chemicals flow to the rescue. One of those chemicals is histamine.
Histamine stretches out a blood vessel like a stocking, opening up little holes to allow special healing cells to leak out. You might be familiar with a certain side effect: Histamine can make scars itch.