Visual Stimuli Linked to Itching in Atopic Dermatitis
Itch videos intensify itch perception and prolong scratching in atopic dermatitis patients
THURSDAY, March 31 (HealthDay News) -- Atopic dermatitis patients report higher itch intensity and scratch more frequently upon watching itch videos, according to a study published online March 17 in the British Journal of Dermatology.
Alexandru D.P. Papoiu, M.D., Ph.D., from the Wake Forest University School of Medicine in Winston-Salem, N.C., and colleagues investigated whether exposure to visual itch cues induces or intensifies local itch in 14 healthy volunteers and 11 atopic dermatitis patients. Participants were randomized to receive local itch stimulus (histamine) or mock stimulus (saline), and were asked to watch short video clips of people scratching or sitting idly. At each session, each participant's intensity of itch perception was assessed on the Visual Analog Scale (VAS), and spontaneous scratching induced by visual cues was monitored.
The investigators found that nine atopic subjects reported an increase in itch sensation, and six healthy volunteers indicated higher VAS ratings of itch while watching an itch video. Compared to healthy volunteers, atopic subjects with mock stimulus doubled the duration of scratching, scratched beyond the local itch site, and had significant increases in itch sensation, from 0.82 to 2.51 on VAS. Compared to healthy volunteers, atopic subjects with histamine stimulus doubled the duration of scratching which was directed towards areas widely distributed over the body, and their itch perception increased significantly from 3.5 to 5.9 on VAS after repeating histamine stimulus.
"Human susceptibility to develop itch when exposed to visual cues is confirmed and it appears amplified in atopic dermatitis sufferers," the authors write.