EFFECTS OF MENTHOL AND COLD ON HISTAMINE-INDUCED ITCH AND SKIN REACTIONS IN MAN

The effects of cooling and topical application of menthol on histamine -induced itch, wheal and flare reactions of the left lower arm were in vestigated in a threefold cross-over design with 15 healthy male volun teers. Lowering skin temperature by cooling from 32.8 +/- 0.3 degrees C to 29.7 +/- 0.5 degrees C reduced itch intensity from 260 +/- 47 uni ts to 55 +/- 12 units (visual analogue scale) and flare diameters from 39.0 +/- 2.0 mm to 30.2 +/- 1.8 mm; wheal reactions were not affected . A similar reduction in itch was found under menthol (42 +/- 14 units ) although skin temperature was not decreased. These findings suggest a central inhibitory effect of cold sensitive A-delta fibre activation on itch.