The effect of touch on itch- The influence of affective touch and interpersonal touch on itch relief

Abstract

Itch is caused by a variety of conditions, but for some patients effective treatment is still lacking. Itch is processed via unmyelinated C-fibers and is influenced by counter stimuli that rely on similar fibers. Affective touch is a pleasant touch that relies on a subgroup of C-fibers (CTafferents) and could be effective for itch relief. CT-afferents are shown to respond optimally to typical skin temperature, thus the present study investigates whether interpersonal touch has an additional relieving effect on itch. In this study, itch was electrically induced in four touch conditions: 1) impersonal non-affective touch, 2) impersonal affective touch, 3) interpersonal non-affective touch and 4) interpersonal affective touch. A brush was used for impersonal touch and fingers of the experimenter for interpersonal touch, with slow strokes (3cm/s) for affective touch and fast strokes for non-affective touch (18 cm/ s). The duration of a condition was 10 minutes, with 5 itch measurements on a VAS-scale. The results showed that affective and interpersonal touch do not have a greater relieving effect on itch compared to non-affective and impersonal touch. In addition, no relationship between the experienced pleasantness of touch and itch relief was found. In conclusion, this study could not provide supporting evidence that optimal CT-afferents activation by touch has an additional relieving effect on itch. An attention effect is proposed as alternative explanation. In order to draw firm conclusions, further research with methodological adjustments is needed.