Itching is an unpleasant sensation of damage to cells in our skin. As a result of the damage, substances like histamine are set free and irritate the nerve fibres in the skin. These send signals to the central nervous system which provokes an itch. Itch signals are received by the same part of the brain that receives pain signals. Scratching provides a "counterirritation" that distracts the brain from the original itch. Scratching interferes with the pain signals of itch by activating pain receptors in the same area where the itch occurred. However, the relief is usually temporary. Scratching sometimes releases pain-reducing endorphins. The pain neurons become temporarily overwhelmed, which masks the itching sensation and gives releif.