The Neurohistology and Neurophysiology of the Itch Sensation in Man

The skin is a vast sentient surface, attuned to numerous environmental changes. Although it was first viewed as representing only the fifth sense, i. e., touch, the last century of research has disclosed that the skin is a far more complex sensory receptor. This area of study has long been an actively disputative one, and indeed within the year critical essays have challenged all previously held concepts of both the form and the function of sensory receptors in the skin of man. It is our purpose to review the field of knowledge concerning the itch sensation in man, to report experimental observations of our own, and to attempt an interpretative analysis of the neurophysiological basis for itching. The modern era of conceptual thinking on the problem of sensory reception in the skin began in 1838, when Johannes Müller¹enunciated his doctrine of specific energy, i. e., he