Mechanisms Underlying the Nocibo Effect of Contagious Itch. in Both Histaminergic and Nonhistaminergic Itch

NCT07255092 | Not Yet Recruiting DMC

• 1 other identifier: N-20250017 Project 3
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

ITCH

Outcome Measures

Primary Outcomes (2)

• Measuring pain by computerized Visual Analog Scale Scoring

  The investigators will ask the subjects to rate the sensation of pain on a 100 mm VAS scale ranging from 0 to 100 where 0 indicates" no pain" and 100 indicates "worst pain imaginable".

  Immediately after the intervention

• Measuring itch by computerized Visual Analog Scale Scoring

  The investigators will ask the subjects to rate the sensation of itch on a 100 mm VAS scale ranging from 0 to 100 where 0 indicates "no itch" and 100 indicates "worst itch imaginable".

  Immediately after the intervention

Secondary Outcomes (8)

• Pain Catastrophizing Scale (PCS).

  Baseline

• Itch Catastrophizing Scale (ICS)

  Baseline

• Learned Helplessness Scale (LHS)

  Baseline

• Depression, Anxiety, Stress Scale (DASS-21)

  Baseline

• Reinforcement Sensitivity Theory - Personality Questionnaire (RST-PQ).

  Baseline

Study Arms (1)

Contagious itch

EXPERIMENTAL

A contagious itch will be induced by a video (without audio) showing people scratching.

Other: Histamine; Other: Cowhage (Mucuna Pruriens); Other: Placebo

Interventions

Histamine OTHER

To deliver histamine, standard allergy skin prick test (SPT) lancets are applied

Contagious itch

Cowhage (Mucuna Pruriens) OTHER

The spicules will be manually inserted. Approximately 30-35 spicules are gently rubbed into a 1 cm diameter skin area on the forearm/face

Contagious itch

Placebo OTHER

To deliver steril water, standard allergy skin prick test (SPT) lancets are applied

Contagious itch

Eligibility Criteria

• Age: 18 Years - 60 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• years
• Speak and understand English

You may not qualify if:

• Pregnancy or lactation
• Drug addiction defined as any use of cannabis, opioids, or other drugs
• Previous or current history of neurological, immunological, musculoskeletal, cardiac disorder or psychiatric diagnoses that may affect the results (e.g., neuropathy, muscular pain in the upper extremities, anxiety, depression, schizophrenia, etc.)
• Moles, wounds, scars, or tattoos in the area to be treated or tested
• Current use of medications that may affect the trial such as antihistamines and pain killers
• Skin diseases
• Consumption of alcohol or painkillers 24 hours before the study days and between these
• Acute or chronic pain and itch
• Participation in other trials within 1 week of study entry (4 weeks in the case of pharmaceutical studies)
• Contraindications to capsaicin, including intolerance to chili or burns or wounds at the application site
• The subject is assessed as unable to engage in the necessary cooperation required by the study

Sponsors & Collaborators

• Aalborg University: lead

Study Sites (1)

Aalborg University

Gistrup, Denmark, 9620, Denmark

Location

MeSH Terms

Interventions

Histamine

Intervention Hierarchy (Ancestors)

Biogenic Monoamines; Biogenic Amines; Amines; Organic Chemicals; Ethylamines; Imidazoles; Azoles; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Autacoids; Inflammation Mediators; Biological Factors

Central Study Contacts

Silvia Lo Vecchio, PhD

CONTACT

+4521397785; slv@hst.aau.dk

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Study Record Dates

• First Submitted: November 20, 2025
• First Posted: November 28, 2025
• Study Start: December 1, 2025
• Primary Completion (Estimated): December 31, 2026
• Study Completion (Estimated): December 31, 2028
• Last Updated: December 4, 2025

Record last verified: 2025-11

Locations

DK (1)