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

NCT ID: NCT07255092

Last Updated: 2025-12-04

Basic Information

• Recruitment Status: NOT_YET_RECRUITING
• Clinical Phase: NA
• Total Enrollment: 30 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-12-01
• Study Completion Date: 2028-12-31

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

Study Design

• Allocation Method: NA
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: NONE

Study Groups

Contagious itch

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

Group Type: EXPERIMENTAL

Histamine

Intervention Type: OTHER

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

Cowhage (Mucuna Pruriens)

Intervention Type: 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

Placebo

Intervention Type: OTHER

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

Interventions

Histamine

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

Intervention Type: OTHER

Cowhage (Mucuna Pruriens)

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

Intervention Type: OTHER

Placebo

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

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• 18-60 years
• Speak and understand English

Exclusion Criteria

• 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

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 60 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Aalborg University

OTHER

Sponsor Role: lead

Responsible Party

Silvia Lo Vecchio

Associate Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

Aalborg University

Gistrup, Denmark, Denmark

Countries

Denmark

Central Contacts

Silvia Lo Vecchio, PhD

Role: CONTACT

slv@hst.aau.dk

+4521397785

Facility Contacts

Silvia Lo Vecchio, PhD

Role: primary

slv@hst.aau.dk

21397785

Giulia Erica Aliotta, PhD

Role: backup

gea@hst.aau.dk

Other Identifiers

N-20250017 Project 3

Identifier Type: -

Identifier Source: org_study_id