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

Not Applicable

Completed

• Conditions: Cowhage; Histamine

• Registration Number: NCT06154824
• Lead Sponsor: Aalborg University

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.

Study Timeline

• Study First Submitted: 2023-11-20
• Study First Submitted QC: 2023-11-30
• Study First Posted: 2023-12-04
• Study Start: 2023-12-15
• Status Verified: 2024-01
• Primary Completion: 2024-12-31
• Study Completion: 2025-05-30
• Last Update Submitted: 2025-05-30
• Last Update Posted: 2025-06-04

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 30

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)

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Primary Outcome Measures

Name	Time	Method
Assessment of itch intensity	1 minute post itch provocation	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'.
Assessment of pain intensity	1 minute post itch provocation	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'.

Secondary Outcome Measures

Name	Time	Method
Alloknesis	12 minutes post itch provocation	Alloknesis sensation is measured using a standardized sensory brush (SENSELab Brush-05, Somedic AB, Hörby, Sweden) exerting a force of 200 to 400 mN.
Superficial blood perfusion	10 minutes post itch provocation	The evoked cutaneous inflammation (quantified by superficial blood perfusion) will be measured by full-field laser perfusion imaging.
Mechanically evoked itch	15 minutes post itch provocation	Mechanically evoked itch is measured using three von Frey filaments of 4.08, 4.16 and 4.31 (1.0, 1.4, 2.0 g, respectively) (North Coast Medical, Gilroy, CA). The center of the skin area is stimulated by 3 pricks, repeated 3 times in short succession. After a total of 9 stimulations, the participants will report the itch elicited on a numerical rating scale (NRS) from 0 to 10 (0 = "no itch"; 10 = "worst imaginable itch").

Trial Locations

Locations (1)

Aalborg University; 🇩🇰 Aalborg, Denmark