Pruritic and antipruritic colors: An exploratory pilot study

Itch is the commonest skin-related symptom and can be influenced by visual cues as exemplified by the phenomenon of "contagious itch." Colors are visual cues able to modify somatosensory inputs. We explored the relationship of colors and itch and the impact of color viewing on itch intensity. In this cross-sectional study, patients suffering from itch with a mean intensity of ≥2 on a Numerical Rating Scale during the last 7 days were evaluated. The study consisted of a questionnaire-based part using The Manchester Color Wheel and the ItchyQoL, followed by an interventional part. All 72 itch patients were able to match their itchy sensation with a color: In 68 patients (94.4%) this "pruritic" basic color was red. Likewise, all patients were able to define a subjective "antipruritic" color: The leading basic color choice was blue (31/72, 43.0%) followed by green (21/72, 29.1%), yellow (7/72,9.7%) and others. The impairment of the itch-related quality of life (as measured by the ItchyQoL) correlated with the brightness and saturation of the pruritic and antipruritic colors. Ten patients were visually exposed to their subjective antipruritic and pruritic color during 10 minutes resulting in a significant decrease and increase of itch intensity compared to baseline (5.1 ± 1.52 vs. 2.8 ± 1.47 [0-10 Numerical Rating Scale, NRS], p=0.0004 and 4.9 ± 1.66 vs. 6.8± 2.09 NRS, p=0.0009). These results indicate that itch can be modified by color viewing and colors matter when treating itch patients. However, further investigations are required to elucidate the therapeutic potential of colors in itch patients.