Repetitive Applications of Pruritogens and Effects of a Cutaneous-induced Pain Stimulation on Nonhistaminergic Itch Perception

NCT06154824 | Completed DMC

• 1 other identifier: N-20210046 1st project
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

In This experiment, the investigators would like to test following hypotheses: repetitive cutaneous administration of pruritogens will lead to a more robust and longer lasting itch sensation compared with a single application. The aim of this project is to investigate a new itch model based on repetitive administration of three different pruritogens: histamine (histaminergic itch), cowhage, and BAM 8-22 (non-histaminergic itch).

Conditions

Histamine; Cowhage

Outcome Measures

Primary Outcomes (2)

• Assessment of itch intensity

  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 post itch provocation

• Assessment of pain intensity

  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 post itch provocation

Secondary Outcomes (3)

• Superficial blood perfusion

  10 minutes post itch provocation

• Alloknesis

  12 minutes post itch provocation

• Mechanically evoked itch

  15 minutes post itch provocation

Study Arms (2)

1st pruritogen

EXPERIMENTAL

The study takes place over two sessions over a period of 7 days. The duration of the sessions is approx. 4 hours in total. In the 1st session, a squared area of 4x4 cm will be selected at the center of each middle forearm of the subject. The two areas will be randomly treated with one of the following substances: cowhage, histamine, BAM 8-22 or vehicle. Each substance will be applied for 10 minutes, during which the pain/itch following the substance application will be monitored. Twenty minutes after each application, the measurements with FLPI will be conducted. Then the measurements of alloknesis and mechanically evoked itch, will be conducted. This procedure will be repeated three times for each substance; so in total each substance will be applied three times, each application lasting 10 minutes.

Other: Cowhage

2nd pruritogen

EXPERIMENTAL

The study takes place over two sessions over a period of 7 days. The duration of the sessions is approx. 4 hours in total. In the 1st session, a squared area of 4x4 cm will be selected at the center of each middle forearm of the subject. The two areas will be randomly treated with one of the following substances: cowhage, histamine, BAM 8-22 or vehicle. Each substance will be applied for 10 minutes, during which the pain/itch following the substance application will be monitored. Twenty minutes after each application, the measurements with FLPI will be conducted. Then the measurements of alloknesis and mechanically evoked itch, will be conducted. This procedure will be repeated three times for each substance; so in total each substance will be applied three times, each application lasting 10 minutes.

Other: Histamine

Interventions

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

Cowhage OTHER

25 spicules will be inserted in the centre 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

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, Denmark, 9260, 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

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON 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: Assistant Professor

Model Details: The participants will randomly receive 3 consecutive applications of cowhage and histamine.

Study Record Dates

• First Submitted: November 20, 2023
• First Posted: December 4, 2023
• Study Start: December 15, 2023
• Primary Completion: December 31, 2024
• Study Completion: May 30, 2025
• Last Updated: June 4, 2025

Record last verified: 2024-01

Data Sharing

• IPD Sharing: Will not share

Locations

DK (1)