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

NCT ID: NCT06154824

Last Updated: 2025-06-04

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 30 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2023-12-15
• Study Completion Date: 2025-05-30

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).

Detailed Description

Chronic itch affects approximately a fifth of the global population and is associated with substantial negative consequences for the affected individuals. Furthermore, there is a lack of efficient treatment options for chronic itch. In order to mimic a clinical itch condition as presented in patients, the aim of the 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). The hypothesis is that repetitive cutaneous administration of pruritogens will lead to a more robust and longer-lasting itch sensation compared with a single application. This proposal for a new itch model could better mimic clinical itch conditions and be used to investigate fundamental mechanisms, new anti-pruritic drugs, and their possible mechanisms of action.

Conditions

Histamine; Cowhage

Study Design

• Allocation Method: NON_RANDOMIZED
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: SINGLE

Study Groups

1st pruritogen

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.

Group Type: EXPERIMENTAL

Cowhage

Intervention Type: 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

2nd pruritogen

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.

Group Type: EXPERIMENTAL

Histamine

Intervention Type: 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

Interventions

Histamine

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

Intervention Type: OTHER

Cowhage

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

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• Healthy men and women
• 18-60 years
• Speak and understand English

Exclusion Criteria

• 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)

• 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

Assistant Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

Aalborg University

Aalborg, Denmark, Denmark

Countries

Denmark

Other Identifiers

N-20210046 1st project

Identifier Type: -

Identifier Source: org_study_id