Pruritus
Conditions
Brief summary
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.
Interventions
DRUGCapsaicin 24 Hours
Dermal patches for transdermal application of Capsaicin, applied for 24 hours
DRUGCapsaicin 1 Hour
Dermal patches for transdermal application of Capsaicin, applied for 1 hour
OTHERQutenza Demo Patch
Dermal patches mimicking active Qutenza patches. Used as control in comparison of Capsaicin efficacy. Applied for 24 hours.
Sponsors
Hjalte Holm Andersen
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 60 Years
Healthy volunteers
Yes
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)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Itch intensity | Assessed continuously at 0-10 minutes following itch provocation | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Neurogenic inflammation | Assessed 11 minutes after itch provocation | Neurogenic inflammation in the treated area is assessed using full-field laser perfusion imaging (FLPI) |
| Changes in sensitivity to touch-evoked itch | Assessed before, and at 12-15 minutes following itch provocation | 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. |
| Wheal size | Assessed at 10 minutes following itch provocation | 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. |
| Pain intensity | Assessed continuously at 0-10 minutes following itch provocation | 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. |
| Pain during capsaicin application | 24 hours after first application of capsaicin patch | Peak and average numerical rating scale (NRS) scores ('0-10, 'no pain-worst imaginable pain') are reported by subjects for each patch. |
Countries
Denmark
Outcome results
None listed