Itch
Conditions
Brief summary
This third sub-project aims to evaluate the interaction between the TRPM8 receptor and pruritus by studying the anti-pruritic effect of TPRM8-agonist L-menthol on histaminergic and non-histaminergic itch induced using three different pruritogens: histamine, cowhage and papain.
Interventions
OTHERPapain
Papain will be applied using cowhage spicules inactivated by heat
OTHERHistamine
To deliver histamine, standard allergy skin prick test (SPT) lancets are applied
OTHERCowhage
Cowhage spicules are 1-2 mm in length and have a diameter of 1-3 μm. The spicules are inserted by gently rubbing 30-35 spicules into a 1 cm diameter skin area.
OTHERL-menthol
A 1 mL aliquot is dispensed onto a 2,5 × 2,5 cm cotton pad and placed on a 6 × 6 cm sheet of medical tape.
Sponsors
Aalborg University
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 60 Years
Healthy volunteers
Yes
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, dermatological, immunological musculoskeletal, cardiac disorder or mental illnesses that may affect the results (e.g. neuropathy, muscular pain in the upper extremities, etc.). * 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 * Moles, scars or tattoos in the area to be treated or tested. * Hypersensitivity to papaya and mango fruit, cashew nuts, rubber latex * Consumption of alcohol or painkillers 24 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 |
|---|---|---|
| Measuring itch intensity by computerized Visual Analog Scale Scoring | For 15 minutes | We will ask the subjects to rate the sensation of itch on a 100 mm VAS scale ranging from 0 to 100 where 0 indicates no itch and 100 indicates worst itch imaginable |
| Measuring pain intensity by computerized Visual Analog Scale Scoring | For 15 minutes | We will ask the subjects to rate the sensation of pain on a 100 mm VAS scale ranging from 0 to 100 where 0 indicates no pain and 100 indicates worst pain imaginable. |
| Superficial blood perfusion measurement | After 15 minutes | Superficial blood perfusion is measured by a Speckle contrast imager |
| Measuring Alloknesis | 15 minutes | Alloknesis is measured by using mildly pruritic, non-painful von Frey nylon filaments of a predetermined intensity (generally 5-30 milliNewton of force). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Measurement of Pain to Supra-threshold Heat Stimuli | 15 minutes | The tests for thermal sensation will all be conducted using a PATHWAY ATS (Medoc Ltd, Israel) thermal sensory testing device. |
| Measurement of Mechanical Pain Thresholds (MPT) | 15 minutes | This test is conducted using a pin-prick set. |
| Measurement of Cold Detection Thresholds (CDT) | 15 minutes | The tests for thermal sensation will all be conducted using a PATHWAY ATS (Medoc Ltd, Israel) thermal sensory testing device. |
| Touch Pleasantness (TP) | 15 minutes | Pleasant touch sensation measured using a standardized sensory brush |
| Measurement of Mechanical Pain Sensitivity (MPS) | 15 minutes | This test is conducted using a pin-prick set. |
| Measurement of Cold PainThresholds (CPT) | 15 minutes | The tests for thermal sensation will all be conducted using a PATHWAY ATS (Medoc Ltd, Israel) thermal sensory testing device. |
| Measurement of Heat Pain Thresholds (HPT) | 15 minutes | The tests for thermal sensation will all be conducted using a PATHWAY ATS (Medoc Ltd, Israel) thermal sensory testing device. |
| Measurement of Warm Detection Thresholds (WDT) | 15 minutes | The tests for thermal sensation will all be conducted using a PATHWAY ATS (Medoc Ltd, Israel) thermal sensory testing device. |
Countries
Denmark
Outcome results
None listed