ITCH

Very little is currently known about the pathophysiology of pruritus sine materia according to the etiology. The creation of this cohort should make it possible to improve our clinical and biological knowledge according to the etiology, by collecting blood, skin, feces, and clinical data.

This is a prospective, single-arm, open-label, pilot clinical study to evaluate the efficacy and safety of topical 10% high-concentration 35 kDa hyaluronan (HA35) gel for ultra-rapid relief of moderate-to-severe skin pruritus from diverse etiologies (eczema, neurodermatitis, insect bites, urticaria, postoperative wound itch). Eligible participants will receive a single topical application of HA35 gel. The primary objective is to assess pruritus relief at 10 seconds, 45 minutes, 8 hours, 12 hours, and 24 hours post-application. Safety and local skin tolerability will be evaluated throughout the observation period. This is a minimal-risk, non-pharmacological, non-invasive intervention.

This study is being done to obtain descriptive classifications of pruritus using a patient directed survey system and assess change in pruritus over time in patients with Atopic Dermatitis over 4 weeks with use of topical Roflumilast cream 0.15% QD.

The study consists of one experimental session of approximately 1½ hours. The participant will fill in a series of questionnaires about how you perceive itch and pain, and about some traits of your personality, such as depression, anxiety and stress. Afterwards, three areas will be selected on each forearm of the subjects. Two areas will be treated with histamine, two with cowhage, and two with vehicle. One application of each substance will be conducted including the contagious itch component. During the 10 minutes of the application of the pruritogens, itch and pain will be continuously monitored using a VAS scale.

The study consists of one experimental session of approximately 1½ hours. The participant will fill in a series of questionnaires about how you perceive itch and pain, and about some traits of your personality, such as depression, anxiety and stress. Afterwards, two areas will be selected on each forearm of the subjects. The four areas will be treated with the same vehicle cream for 20 minutes, in order to test the placebo effect. At the end of the cream application, two areas will be randomly treated with histamine while cowhage will be applied on the other two areas. During the 10 minutes of the application of the pruritogens, itch and pain will be continuously monitored using a Visual Analog Scale.

The experiment consists of three experimental sessions conducted on three consecutive days. In all experimental sessions, the participant will fill in a series of questionnaires about how you perceive itch and pain, and about some traits of your personality, such as depression, anxiety and stress. In the first session, we will mark six test areas in your face (three on each side on jaw, cheek, and temple, respectively). Thent a series of measure-ments in each test area will be conducted:measurement of the blood flow in the skin and sensitivity tests to pressure, pinprick and stroke with a brush. In the second session, histamine will be applied in one side of the face. On the other side, cowhage spicules will be applied. After 10 minutes, all the tests will be conducted again. The third session will be identical to the second. However, instead of histamine and spicules, patches containing capsaicin will be applied. In the other side, we will apply patches with placebo (i.e., a non-active patch). After 20 minutes all the tests will be conducted again.

Atopic dermatitis (AD) is as chronic, inflammatory skin disorder affecting 20% of the world's population. Intense itch and skin pain are the main symptoms. Research has shown that the proteins interleukins are involved in inflammation and itch in atopic dermatitis. The medicinal product called Lebrikizumab, used for treatment of AD, has shown to block the interleukin called IL-13. The purpose of this experiment is to evaluate the role of IL-13 in itch in both healthy subjects and people with atopic dermatitis.

Chronic itch is a disabling condition with currently limited treatment options. Virtual reality (VR) is a relatively new approach that provides immersion in another environment and has been shown to have a temporary itch mitigating potential. Hypnosis, which is a state of relaxation, has been successfully applied with more long-term treatment effects in the specific case of itch as a result of severe atopic dermatitis. However, hypnosis tends to depend on an individual's susceptibility, or ease, to come into a hypnotic state. A combination of VR and hypnosis (VRH) has been put forward since it may combine the longer lasting effects of hypnosis with VR making the hypnosis more accessible by facilitating imagination. Even though VRH is a promising avenue, it has never been investigated in the context of itch. In this randomized controlled trial, comparing a VRH treatment with a waiting list control group after 6 sessions and at follow-up, it is aimed to assess the effectiveness of VRH in reducing itch along with its psychological burden in adult individuals with therapy-resistant disabling itch.

The aim of this project is to determine the effects of performing a motor imagery task on cortical excitability during acute experimental muscle pain (induced by hypertonic saline), acute histaminergic itch (induced by histamine), and non-histaminergic itch stimulation (triggered by Cowhage). We hypothesize that motor imagery will counteract the alterations in cortical excitability observed during experimental muscle pain and both itch models.