Neuroanatomy and neurophysiology of itch

Authors


Address correspondence and reprint requests to: Joanna Wallengren, MD, PhD, Department of Dermatology, University Hospital, SE-221 85 Lund, Sweden, or email: Joanna.Wallengren@derm.lu.se.

Abstract

ABSTRACT:  The specific pathway of “pure,” histaminergic itch is traced from the mechano-insensitive nerve fibers in the skin to their central cortical projections. Neuropathic itch created at different levels of this anatomical pathway is reviewed. In this review the present author discusses damage to pruritoceptors in the skin, entrapment syndromes, damage to spinal ganglia, nerve root impingement, injury of the spinal cord, and cerebral damage in the distribution of the middle cerebral artery, capsula interna, or thalamus. Itch in inflamed skin resulting from interactions between nerve transmitters and other mediators of inflammation is described.

Ancillary