Department of Dermatology and Allergy, Charité - Universitätsmedizin Berlin, Berlin, Germany.
J Eur Acad Dermatol Venereol. 2019 Sep;33(9):1755-1761. doi: 10.1111/jdv.15743. Epub 2019 Jul 8.
In skin diseases and experimental models of pruritus, pure itch is accompanied by additional sensations that are poorly characterized.
This study compared the sensory qualities evoked by different models of experimentally induced pruritus including skin prick testing (SPT) with histamine or capsaicin and application of cowhage spicules. SPT as a method of capsaicin application was validated for this purpose.
Two pilot experiments were performed in eight healthy volunteers. First, a concentration of 8% capsaicin was identified as evoking a reproducible itch using SPT. Further, a list of the seven most frequently reported sensations was chosen after SPT with 10 mg/mL histamine, 8% capsaicin and application of 40-45 cowhage spicules. Finally, 31 subjects were challenged with the same itch-inducers. Wheal and flare were measured at 10, 20, 40, 60 and 90 min, itch intensity every minute for 30 min, and the overall evaluation of sensory descriptors were recorded on a 100-mm visual analogue scale once itching had subsided.
Skin prick testing with histamine and capsaicin resulted in flare reactions, which were 23% smaller for capsaicin (P < 0.001). Histamine, capsaicin and cowhage-induced pruritus, the duration of which was shorter for cowhage than for histamine (13.5 ± 1.4 vs. 8.8 ± 1.2 min, P = 0.005). Different mediators induced sensations of different intensities. Capsaicin produced less itch and physical urge to scratch than histamine (P = 0.001) and cowhage (P < 0.001). However, both capsaicin and cowhage induced more burning than histamine (P = 0.002 and P = 0.04, respectively). Provocation with cowhage caused more intense sensations of pricking than histamine (P = 0.033).
This study shows that provocation with histamine, capsaicin and cowhage results in itch responses that are different in their duration, the profile of accompanying sensations, and the flare that comes with the itch.
在皮肤疾病和瘙痒实验模型中，单纯瘙痒伴随着特征较差的其他感觉。
本研究比较了不同实验性瘙痒模型引起的感觉质量，包括皮肤点刺试验（SPT）与组胺或辣椒素以及牛毛针的应用。为此，验证了 SPT 作为辣椒素应用的方法。
在 8 名健康志愿者中进行了两项初步试验。首先，确定 8%辣椒素浓度可通过 SPT 引起可重复的瘙痒。此外，在用 10mg/mL 组胺、8%辣椒素和应用 40-45 根牛毛针进行 SPT 后，选择了七种最常报告的感觉的列表。最后，用相同的致痒剂对 31 名受试者进行了挑战。在 10、20、40、60 和 90 分钟时测量风团和红斑，在 30 分钟内每 1 分钟测量瘙痒强度，并在瘙痒消退后在 100mm 视觉模拟量表上记录整体感觉描述符的评估。
组胺和辣椒素的皮肤点刺试验导致了红斑反应，辣椒素的红斑反应小 23%（P<0.001）。组胺、辣椒素和牛毛针引起的瘙痒，牛毛针的持续时间比组胺短（13.5±1.4 与 8.8±1.2 分钟，P=0.005）。不同的介质引起不同强度的感觉。与组胺（P=0.001）和牛毛针（P<0.001）相比，辣椒素引起的瘙痒和搔抓的身体冲动更少。然而，辣椒素和牛毛针引起的烧灼感比组胺更强（P=0.002 和 P=0.04）。与组胺相比，牛毛针引起的刺痛感更强烈（P=0.033）。
本研究表明，组胺、辣椒素和牛毛针的刺激导致了不同持续时间、伴随感觉特征和瘙痒伴随的红斑的瘙痒反应。
