Role of stress in modulation of skin neurogenic inflammation.

There are complex interconnections between the nervous system and the skin highlighted by the impact of stress and neuroendocrine factors on various dermatological conditions. We investigated the influence of stress on skin neurogenic inflammation induced by capsaicin. A total of 31 healthy subjects were randomized into two groups: subjects in the stress group underwent a stress-inducing protocol and those in the control group were exposed to indifferent conditions. Subsequently, topical capsaicin cream was administered on the non-dominant anterior forearm of each subject from the two groups. The assessment of the local inflammatory reaction induced by capsaicin was performed by thermography at 25 and 40 min post-application. In both groups the inflammatory reaction induced by capsaicin was evidenced at 25 min and was maintained at 40 min post-application. However, at 40 min post-application the hyperthermal area was larger in subjects from the stress group, suggesting that stress exposure is associated with an amplification of the mechanisms involved in capsaicin-induced skin neurogenic inflammation.