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.