title: The pleasurability of scratching an itch: a psychophysical and topographical assessment.
abstract: BACKGROUND
  Scratching an itch is perceived as being pleasurable. However, an analysis of topographical variations in itch intensity, the effectiveness of scratching to provide itch relief and the associated pleasurability has not been performed at different body sites.
  
  
  OBJECTIVE
  To examine the role of scratching pleasurability in providing itch relief by investigating whether itch intensity is perceived differently at three different sites and to assess a potential correlation between the pleasurability and itch attenuation induced by scratching.
  
  
  METHODS
  Itch was induced on the forearm, ankle and back using cowhage spicules in 18 healthy subjects. These sites were subsequently scratched by an investigator with a cytology brush immediately following itch induction. The intensity of itch with and without scratching at these sites and the pleasurability of scratching were recorded by taking visual analogue scale ratings at 30-s intervals.
  
  
  RESULTS
  Mean itch intensity and scratching pleasurability ratings at the ankle and back were significantly higher than on the forearm. For the forearm and ankle, the greater the itch while scratching, the higher was the pleasurability. A higher baseline itch was linked to a higher itch reduction secondary to scratching in all tested areas. Pleasurability paralleled the curve of itch reduction for the back and forearm; however, scratching pleasurability at the ankle remained elevated and only slightly decreased while itch was diminishing.
  
  
  CONCLUSIONS
  There are topographical differences in itch intensity, the effectiveness of scratching in relieving itch and the associated pleasurability. Experimental itch induced by cowhage was more intensely perceived at the ankle, while scratching attenuated itch most effectively on the back.
authors.affiliation: Department of Dermatology Neurobiology & Anatomy, and Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
authors.forename: G A
authors.initials: GA
authors.lastname: Bin Saif
authors.forename: A D P
authors.initials: AD
authors.lastname: Papoiu
authors.forename: L
authors.initials: L
authors.lastname: Banari
authors.forename: F
authors.initials: F
authors.lastname: McGlone
authors.forename: S G
authors.initials: SG
authors.lastname: Kwatra
authors.forename: Y-H
authors.initials: YH
authors.lastname: Chan
authors.forename: G
authors.initials: G
authors.lastname: Yosipovitch
mesh_terms: D000328:Adult; D000842:Ankle; D001415:Back; D005260:Female; D005542:Forearm; D006801:Humans; D008297:Male; D008875:Middle Aged; D057181:Pleasure; D011537:Pruritus / Q000523:psychology*; D055815:Young Adult