Why Does It Itch When A Wound Heals?

Itching, as stated in the previous post, is caused by the release of a substance known as histamine that stimulates the nerve endings. When tissues become inflamed due to the invasion of bacteria or by trauma such as heat, chemicals or a cut, histamine is released from the cells to the tissues. And, since histamine is a powerful vasodilator, it increases blood flow and the permeability of the blood capillaries in the vicinity of the wound. Apart from this a number white blood cells known as basophils increases during healing. Basophils contains a huge amount of histamine which diffuses into the nearby skin and stimulates the nerve endings, which in turn, leads to itching.

How Does Scratching Stop Itching?

When our cells get damaged itching results. Due to this small damage substances such as histamine (the amine that plays a role in allergic phenomena and the widening of blood vessels) are freed and which irritates the nerves and fibers in the skin. This irritation sends signals similar to pain to the central nervous system. There is a similarity between telephone lines and a switchboard. The function of a switchboard is to route incoming calls and to ensure that only one line at a time is connected to a particular numbered telephone. This effectively blocks the telephone from other incoming calls. Similarly, the itch signal can be blocked by occupying the central nervous system by another incoming message like the sensation of scratching, which is less irritating.