Pruritic skin diseases, psychological stress, and the itch sensation. A reliable method for the induction of experimental pruritus

Abstract

A method of inducing controlled levels of terminable itching was developed. This method consists of administering constant monophasic pulsations of electric current by means of noninvasive electrodes. Once experimental pruritus had been reliably reproduced, two variables, hypothesized to be relevant to the perception of itching, were investigated, viz, the presence of a positive or a negative history of a pruritic dermatosis, and the presence of a high or low level of psychological stress. Both variables were found to be related to the perception of itching, but in different manners. A positive history of a pruritic dermatosis lowered the threshold for the perception of itch stimuli, while a high level of psychological stress enhanced the ability to discriminate among the more intense itch stimuli, with no effect on the itch threshold.

Neuroselective transcutaneous electric stimulation reveals body area–specific differences in itch perception

“…3 Recently, microneurography has demonstrated that one subset of primary afferent C-fibers is almost exclusively histamine sensitive and is probably the primary afferent whose activity elicits the itch sensation, suggesting the presence of a new class of afferent nerve fibers. 4 As for physical stimuli, electrically evoked itch has also been reported by several authors, [5][6][7][8] although the electrode, frequency, and pulse duration used for the electric stimulation varied from study to study. In addition, the electrodes, the pulse generator, or the electric circuit was constructed by each individual laboratory.…”

“…Electrically evoked itch has been previously reported. [5][6][7] Ikoma et al 20 succeeded in provoking intense itch by transcutaneous electrical stimulation using very localized electrodes. The induced itch was characterized by delayed perception and long pulse duration ([2 ms), which suggested that unmyelinated afferents underlie the electrically evoked itch.…”

Psychosomatics and Dermatology: Comparison between Objective Data and Subjective Impressions Given by Patients and Dermatologists

“…Table 1 shows the cut-off point values. (3) According to the literature [15,20,21,34,40,41] we compared the patients with different dermatological diagnoses in whom a psychological component in the etiology of the disease was suspected (PI 3 group, n = 152) with dermatological patients in whom such a component is not suspected (NPI 3 group, n = 353). Tables 2 and 3 list the different diagnoses in the PI 3 and NPI 3 group, respectively.…”

Psychosomatic factors in pruritus

“…59–62 An experimental study found that a high level of psychological stress enhanced the subjects’ ability to discriminate higher intensities of itch stimuli. 63 Patients with hand dermatoses, who feel that their disease severity is more strongly associated with stress, experienced more itch. 64 …”