NCT07122973

Topographical Distribution of Itch and Pain Receptors

Pain and Itch Neuromodulation: Effects of Offset Analgesia, Placebo, and Nocebo and Topographical Distribution of Itch and Pain Receptors

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 30 (estimated)
• Sponsor: Aalborg University · Academic / Other
• Sex: All
• Age: 18 Years – 60 Years
• Healthy volunteers: Accepted

Summary

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.

Conditions

• Pain
• Itch

Interventions

Type	Name	Description
OTHER	Histamine	To deliver histamine, standard allergy skin prick test (SPT) lancets are applied
OTHER	Cowhage	The spicules will be manually inserted. Approximately 30-35 spicules are gently rubbed into a 1 cm diameter skin area on the forearm/face
OTHER	Capsaicin 8% Patch	Capsaicin patches (dosage form: transdermal patch 8% Qutenza, Astellas) will be applied on 3 squared areas in the face.
OTHER	Demo patch	Placebo patch (demo patch, containing the same formulation as the active treatment with the exception of capsaicin) will be applied on 3 squared areas in the face.

Timeline

• Start date: 2025-09-17
• Primary completion: 2026-12-31
• Completion: 2028-12-31
• First posted: 2025-08-14
• Last updated: 2025-10-01

Locations

1 site across 1 country: Denmark