EVERYDAY SCIENCE

Detailed explanation-1: -Histamine in the skin originates largely from dermal mast cells and is intimately linked to symptoms of allergy. It follows that the itch associated with acute allergen exposure is a consequence largely due to histamine release from mast cells, presumably interacting with pruriceptive C-fibers.

Detailed explanation-2: -The itch-scratch reflex serves as a protective mechanism in everyday life. However, chronic persistent itching can be devastating. Despite the clinical importance of the itch sensation, its mechanism remains elusive. In the past decade, substantial progress has been made to uncover the mystery of itching.

Detailed explanation-3: -Scratching an itch causes minor pain, which prompts the brain to release serotonin. But serotonin also reacts with receptors on neurons that carry itch signals to the brain, making itching worse.

Detailed explanation-4: -These findings suggest that repetitive abnormal scratching behaviors under acute and chronic itch stimuli may activate mesolimbic dopamine neurons along with pleasant emotions, while the restriction of such scratching behaviors may initially induce the activation of PVN-CRH neurons associated with stress.