Effects of High-concentration Topical Capsaicin on Histaminergic and Non-histaminergic Itch

Hjalte Holm Andersen16 enrolled

Overview

The purpose of this project is to investigate the effect of capsaicin-induced neurogenic inflammation with three different intensities on itch subsequently induced by histamine and cowhage. The hypothesis is that capsaicin-induced pre-established neurogenic inflammation significantly increases susceptibility to itch provocations with cowhage and histamine.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Enrollment

Conditions

Pruritus

Interventions

Capsaicin 24 HoursDRUG

Dermal patches for transdermal application of Capsaicin, applied for 24 hours

Capsaicin 1 HourDRUG

Dermal patches for transdermal application of Capsaicin, applied for 1 hour

Qutenza Demo PatchOTHER

Dermal patches mimicking active Qutenza patches. Used as control in comparison of Capsaicin efficacy. Applied for 24 hours.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 60 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Healthy men and women * 18-60 years * Caucasian descent * Speak and understand English Exclusion Criteria: * Pregnancy or lactation * Drug addiction defined as any use of cannabis, opioids or other drugs * Previous or current neurologic, musculoskeletal or mental illnesses * Lack of ability to cooperate * Current use of medications that may affect the trial * Skin diseases * Consumption of alcohol or painkillers 24 hours before the study days and between these * Moles or tattoos in the area to be irradiated * Exposure of the irradiated area to UV radiation (e.g., sun) 48 hours before the study days and between these * Acute or chronic pain * Participation in other trials within 1 week of study entry (4 weeks in the case of pharmaceutical trials)

Locations (1)

SMI

Aalborg, NJ, Denmark

Outcomes

Primary Outcomes

Itch intensity

Rating of the perceived itch intensity on a visual analogue scale (VAS) App (Aalborg University) as displayed on a tablet computer with a sample rate of 1 Hz.

Time frame: Assessed continuously at 0-10 minutes following itch provocation

Secondary Outcomes

Neurogenic inflammation

Neurogenic inflammation in the treated area is assessed using full-field laser perfusion imaging (FLPI)

Time frame: Assessed 11 minutes after itch provocation

Changes in sensitivity to touch-evoked itch

Three von Frey filaments are applied to the test area before and after itch provocation. Subjects report three NRS scores ('0-10', 'No itch-Worst imaginable itch') for itch induced by von Frey stimulation. Change is calculated by subtracting baseline mean from post-provocation mean NRS scores.

Time frame: Assessed before, and at 12-15 minutes following itch provocation

Wheal size

Histamine wheal size is assessed by measuring the longest diameter of the wheal with a ruler, followed by measuring the orthogonal diameter. The mean of these diameters will represent the wheal size in diameter, reported in mm.

Time frame: Assessed at 10 minutes following itch provocation

Pain intensity

Rating of the perceived pain intensity on a visual analogue scale (VAS) App (Aalborg University) as displayed on a tablet computer with a sample rate of 1 Hz.

Time frame: Assessed continuously at 0-10 minutes following itch provocation

Pain during capsaicin application

Peak and average numerical rating scale (NRS) scores ('0-10, 'no pain-worst imaginable pain') are reported by subjects for each patch.

Data from ClinicalTrials.gov

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