Characterization of Cowhage-induced Pruritus in Sensitive Skin: An Observational Laboratory Study

Abstract

Sensitive skin is a prevalent syndrome, characterized by discomfort in response to mild stimuli, which impacts on quality of life. Pruritus is one of the major symptoms of sensitive skin. However, the pathomechanism of sensitive skin is insufficiently understood. As an experimental model for pruritus, the cowhage skin prick test might provide insight into the understanding of sensitive skin. This study aimed to specify the characteristics of cowhage-induced pruritus in sensitive skin. Female volunteers, 20 with sensitive skin and 20 controls, were recruited. Self-report questionnaires were distributed and the responses evaluated; moreover, alongside assessments by dermatologists, skin physiology assessments, lactic acid sting test, capsaicin test and cowhage skin challenge were performed. Pruritus in sensitive skin was perceived as more intense and longer-lasting than in normal skin, with different qualities of accompanying sensations. Cowhage skin challenge results showed moderate consistency with clinical assessments. The results suggest that cowhage skin challenge could be a new tool for the assessment of sensitive skin.

Cowhage‐induced itch scores and the current perception threshold in assessing sensitive skin: An observational laboratory study

“…2 However, the lactic acid stinging test was suggested to have a lower capacity in distinguishing sensitive skin in comparison with the capsaicin test and cowhage test in our previous study. 14 Cowhage induced a more intense itch in the sensitive group than in the control group, which coincided with our previous work. 14 The active component is mucunain, a cysteine protease that acts on the PAR-2 and PAR-4 subtypes to produce itch.…”

“…14 Cowhage induced a more intense itch in the sensitive group than in the control group, which coincided with our previous work. 14 The active component is mucunain, a cysteine protease that acts on the PAR-2 and PAR-4 subtypes to produce itch. 19 Activated PAR-2 coactivates TRPV1 channels, stimulating the release of neuropeptides.…”

“…Other psychophysiological tests such as the lactic acid stinging test and capsaicin test have been used in sensitive skin 2 . However, the lactic acid stinging test was suggested to have a lower capacity in distinguishing sensitive skin in comparison with the capsaicin test and cowhage test in our previous study 14 …”

“…A modified protocol of the cowhage test was performed in consideration of skin hyperreactivity. 14 Approximately 20 cowhage spicules were applied with a gloved finger on a 2-cm2 area on the face. Spicules were then gently rubbed on the skin for 20 s with a circular motion.…”

“…Cowhage has been studied in a substantial number of studies of itching [11][12][13] and was validated to be useful in identifying sensitive skin by provoking a more intense and longer duration of itch. 14 This study aimed to compare the CPT measurement and the cowhage test for sensitive skin and to investigate the correlation between CPT values and cowhage-itch scores.…”