Itch Sensation Induced by Multiple Applications of Pruritogens (Temporal Summation)

Histamine Clinical Trial

Official title:

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

Clinical Trial Details — Status: Not yet recruiting

Administrative data

• NCT number: NCT06328543
• Other study ID #: N-20210046 4th project
• Status: Not yet recruiting
• Phase: N/A
• Start date: July 1, 2024
• Est. completion date: December 31, 2026

Study information

• Verified date: June 2024
• Source: Aalborg University
• Contact: Silvia Lo Vecchio, PhD
• Phone: +4521397785
• Email: slv[@]hst.aau.dk
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

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

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 the multiple applications of pruritogens (temporal summation). In particular, the purpose is to evaluate if a single application of cowhage/histamine (non-histaminergic and histaminergic itch, respectively) results in a lower itch sensation compared with two overlapped applications of the pruritogens on the same area.

Recruitment information / eligibility

• Status: Not yet recruiting
• Enrollment: 26
• Est. completion date: December 31, 2026
• Est. primary completion date: December 31, 2025
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 60 Years

Eligibility

Inclusion Criteria:

• Healthy men and women

• 18-60 years

• Speak and understand Englis

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)

Related Conditions & MeSH terms

• Cowhage
• Histamine

Intervention

Other:
• 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.
• Cowhage
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.

Locations

Country	Name	City	State
n/a

Sponsors (1)

Lead Sponsor	Collaborator
Aalborg University

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	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
Primary	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	Microvascular reactivity	The evoked cutaneous inflammation (quantified by superficial blood perfusion) will be measured by full-field laser perfusion imaging.	10 minutes after every itch inductions
Secondary	Alloknesis	Alloknesis sensation is measured using a standardized sensory brush (SENSELab Brush-05, Somedic AB, Hörby, Sweden) exerting a force of 200 to 400 mN.	12 minutes after every itch inductions
Secondary	Mechanically evoked itch	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").	15 minutes after every itch inductions