A review of itch: causes, neurophysiology, interpretation, and treatment options

Itch can be one of the most difficult complaints for physicians to treat. The cause of itch, especially if chronic, is often elusive. A body of research has emerged that has shed light on many of the mechanisms governing this common complaint. These mechanisms include the detection of pruritogens (pruritic stimuli) by specific subsets of neurons that transmit and modulate signals through the spinal cord to the brain for interpretation. A host of exogenous and endogeneous pruritogens have been discovered, along with the subsets of neurons, receptors, and pathways responsible for the sensation they cause. This knowledge has yielded numerous topical, systemic, and light-based options for therapy, many of which have been studied and may provide well-tolerated and efficacious long-term treatment for this common complaint.