Itch Sensation Induced by Simultaneous Application of Pruritogens (Spatial Summation)

NCT06328530 | Recruiting DMC

• 1 other identifier: N-20210046 3rd project
• Study Type: interventional
• Target: 24
• Locations: 1 country
• Sites: 1

Brief Summary

In This experiment, the investigators would like to design a new itch model based on the spatial summation of pruritic stimuli. The hypothesis behind this study (spatial summation) is that two simultaneous applications of pruritogens will result in higher itch sensation compared with a single application of pruritogen.

Conditions

Histamine; Cowhage

Outcome Measures

Primary Outcomes (2)

• Assessment of itch

  Immediately following the itch provocations, participants will be instructed to rate the itch intensity for 10 minutes using a digital visual analogue scale (VAS; eVAS Software: Aalborg, University, Denmark), on a tablet. The scale will be measured from 0 to 100, where 0 represents 'no itch' and 100 'worst itch imaginable'.

  1 minute after every itch inductions

• Assessment of pain

  Immediately following the itch provocations, participants will be instructed to rate the pain intensity for 10 minutes using a digital visual analogue scale (VAS; eVAS Software: Aalborg, University, Denmark), on a tablet. The scale will be measured from 0 to 100, where 0 represents 'no pain' and 100 'worst pain imaginable'.

  1 minute after every itch inductions

Secondary Outcomes (2)

• Alloknesis

  12 minutes after every itch inductions

• Mechanically evoked itch

  15 minutes after every itch inductions

Study Arms (2)

1st pruritogen

EXPERIMENTAL

The subproject consists of 2 sessions 3 days apart. Each session consists of 3 parts. In the first session, 3 test areas (4x4 cm) will be selected on the subject's forearms. In part 1, we will apply cowhage in one area. In part 2, we will apply cowhage in two areas on the same arm. In part 3, we will again apply cowhage in 2 areas, one on each arm. In each part, the itch intensity will be measured using a VAS (visual analog scale) for 10 min from the cowhage application. After removal of the cowhage, alloknesis and mechanically evoked itch will be measured in the area selected in part 1.

Other: Cowhage

2nd pruritogen

OTHER

The second session will take place 3 days after the first one and will follow the same procedure as session 1. However, histamine will be applied instead of cowhage. The order of the two sessions will be randomized.

Other: Histamine

Interventions

Cowhage OTHER

25 spicules will be inserted in the center of the predefined skin area on the mandibular area. The spicules will be gently rubbed for 15-20 seconds in circular motion to facilitate epidermal penetration.

1st pruritogen

Histamine OTHER

Histaminergic itch will be evoked by a 1% histamine solution. A droplet of histamine solution will be placed on the predetermined area on the forearm, and the SPT lancet will be pierced through the histamine with 120 g of pressure for 1-2 seconds.

2nd pruritogen

Eligibility Criteria

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

You may qualify if:

• Healthy men and women
• years
• Speak and understand English

You may not qualify if:

• Pregnancy or lactation
• Drug addiction defined as any use of cannabis, opioids, or other addictive drugs
• Previous or current history of neurological (e.g. neuropathy), immunological (e.g. asthma, immune deficiencies, arthritis) musculoskeletal (e.g. muscular pain in the upper extremities,), cardiac disorder, or mental illnesses that may affect the results
• Lack of ability to cooperate
• Current use of medications that may affect the trial such as antihistamines, antipsychotics, and pain killers, as well as systemic or topical steroids
• Skin diseases (e.g. atopic dermatitis, pruritus nodularis, eczema, psoriasis)
• Moles, scars, or tattoos in the area to be treated or tested.
• Consumption of alcohol or painkillers 24 hours before the study days and between these
• Acute or chronic pain
• Participation in other trials within one week of study entry (four weeks in the case of pharmaceutical trials)

Sponsors & Collaborators

• Aalborg University: lead

Study Sites (1)

Aalborg University

Aalborg, 9620, Denmark

RECRUITING

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

Giulia Erica Aliotta, PhD

CONTACT

50290580; gea@hst.aau.dk

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Masking Details: Participant will be blinded about application of pruritogens.
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Model Details: The participants will randomly receive applications of cowhage and histamine.

Study Record Dates

• First Submitted: March 19, 2024
• First Posted: March 25, 2024
• Study Start: April 1, 2024
• Primary Completion: December 31, 2025
• Study Completion (Estimated): December 31, 2026
• Last Updated: May 6, 2024

Record last verified: 2024-05

Locations

DK (1)