The Effect of Halophyte-based Cream on Pain and Itch
- Conditions
- Pain, AcuteItch
- Interventions
- Other: Halophites-based cream 24 hoursOther: Halophites-based cream 48 hoursOther: Vehicle cream 24 hoursOther: Vehicle cream 48 hoursOther: Histamine 1%Other: Cowhage
- Registration Number
- NCT04635254
- Lead Sponsor
- Aalborg University
- Brief Summary
In this study the investigators wish to investigate whether halophyte-based cream applied to the skin can reduce itch applied by means of small needles from the plant mucuna pruriens (also called cowhage) or by histamine (an itch-evoking substance formed in the human body). Further, the investigators wishes to investigate whether long-term application of halophyte-based cream has a pain-relieving effect on heat/cold and pinprick stimulations.
- Detailed Description
Salt-tolerant plants (also called halophytes) can grow in saline soil or directly in salt water (e.g. along coasts). For centuries, these plants have been used in folk medicine, and among other things they are believed to have pain-relieving and anti-inflammatory effect.
Even though experiments have already investigated halophytes as a pain relieving substance, the mechanisms in relation to pain and/or itch are still unknown. Therefore, the investigators wish to investigate whether halophyte-based cream applied to the skin can reduce itch applied by means of small needles from the plant mucuna pruriens (also called cowhage) or by histamine (an itch-evoking substance formed in the human body). Further, the investigators wishes to investigate whether long-term application of halophyte-based cream has a pain-relieving effect on heat/cold and pinprick stimulations.
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- All
- Target Recruitment
- 32
- Healthy men and women
- 18-60 years
- Speak and understand English
- Pregnancy or lactation
- Drug addiction defined as any use of cannabis, opioids or other drugs
- Previous or current neurologic, musculoskeletal 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 antihistamine medications or pain killers
- Skin diseases
- 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)
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- PARALLEL
- Arm && Interventions
Group Intervention Description Halophites-based cream 24 hours Vehicle cream 24 hours A 2 gram amount of Halophites-based cream will be applied under occlusion (TegaDerm tape) in a 4x4 cm squared area. Halophites-based cream 24 hours Cowhage A 2 gram amount of Halophites-based cream will be applied under occlusion (TegaDerm tape) in a 4x4 cm squared area. Halophites-based cream 24 hours Histamine 1% A 2 gram amount of Halophites-based cream will be applied under occlusion (TegaDerm tape) in a 4x4 cm squared area. Halophites-based cream 48 hours Vehicle cream 48 hours A 2 gram amount of Halophites-based cream will be applied under occlusion (TegaDerm tape) in a 4x4 cm squared area. Halophites-based cream 24 hours Halophites-based cream 24 hours A 2 gram amount of Halophites-based cream will be applied under occlusion (TegaDerm tape) in a 4x4 cm squared area. Halophites-based cream 48 hours Halophites-based cream 48 hours A 2 gram amount of Halophites-based cream will be applied under occlusion (TegaDerm tape) in a 4x4 cm squared area. Halophites-based cream 48 hours Histamine 1% A 2 gram amount of Halophites-based cream will be applied under occlusion (TegaDerm tape) in a 4x4 cm squared area. Halophites-based cream 48 hours Cowhage A 2 gram amount of Halophites-based cream will be applied under occlusion (TegaDerm tape) in a 4x4 cm squared area.
- Primary Outcome Measures
Name Time Method Superficial blood perfusion 48 hours after cream application Superficial blood perfusion is measured by a Speckle contrast imager (FLPI, Moor Instruments, England).
Pain intensity 48 hours after cream application The subject will rate the pain sensation on a 100 millimeter Visual Analog Scale from 0 to 100., where 0"indicates no pain and "100" worst pain imaginable
Itch intensity 48 hours after cream application The subject will rate the itch sensation on a 100 millimeter Visual Analog Scale from 0 to 100., where 0"indicates no itch and "100" worst itch imaginable
Measuring Alloknesis 48 hours after cream application Alloknesis is measured by using mildly pruritic, non-painful von Frey nylon filaments of a predetermined intensity (generally 5-30 miliNewton of force).
Trans-epidermal Water Loss (TEWL) 48 hours after cream application TEWL is a non-invasive and pain free measuring technique in which a 2x2 cm hollow probe with two small humidity gauges and two thermometers is placed lightly on the skin for 10-25 seconds. These collectively establish a precise humidity gradient in a 2 cm vicinity of the skin, representative for the point-loss of water though the epidermis.
- Secondary Outcome Measures
Name Time Method Measurement of Mechanical Pain Sensitivity (MPS) 48 hours after cream application This test is performed using the same pin-prick set as for the MPT test. Starting with the lightest, each stimulator is applied at a rate of 2 s on, 2 s off in an ascending order, and the subject will be asked to give a pain rating for each stimulus on a scale from 0-10 (where 0 indicates ''no pain'', and 10 indicates the ''worst imaginable pain''). This procedure will be repeated twice.
Measurement of Warm Detection Thresholds (WDT) 48 hours after cream application The tests for thermal sensation will all be performed using a PATHWAY ATS (Medoc Ltd, Israel) thermal sensory testing device. A thermode stimulator of 3x3 cm will be placed on the treated/placebo areas and kept in place by means of Velcro tape. During the first 8 seconds, the temperature raises 1°C per second from a starting temperature of 32°C until the subject perceives a temperature change (warm sensation) and presses a button that will terminate the measurement and return the temperature to baseline at a rate of 5°C /s. A cut-off temperature of 52°C will be used.
Measurement of Cold Pain Thresholds (CPT) 48 hours after cream application The tests for thermal sensation will all be performed using a PATHWAY ATS (Medoc Ltd, Israel) thermal sensory testing device. A thermode stimulator of 3x3 cm will be placed on the treated/placebo areas and kept in place by means of Velcro tape. During the first 8 seconds, the temperature decreases 1°C per second from a starting temperature of 32°C until the subject detects a painful sensation and presses a button that will terminate the measurement and return the temperature to baseline at a rate of 5°C /s. A cut-off temperature of 0°C will be used.
Measurement of Mechanical Pain Thresholds (MPT) 48 hours after cream application This test is performed using a pin-prick set (Aalborg University, Aalborg). The set consists of 8 needles each having a diameter of 0.6 mm and different force applications: 0.8, 1.6, 3.2, 6.4, 12.8, 25.6, 50.1 and 60.0 g. Starting with the lightest, each stimulator is applied at a rate of 2 s on, 2 s off in an ascending order until the first perception of sharpness is reached. The final threshold is the geometric mean of five series of ascending and descending stimuli.
Measurement of Pain to Supra-threshold Heat Stimuli: 48 hours after cream application Again, the tests will be performed by using the PATHWAY ATS thermal sensory testing device. The subjects will have to rate the pain to three suprathreshold heat pain stimuli (starting and ending at 34°C with an increase and decrease of 5°C and 4 s plateau at 50°C) applied on the treated/placebo areas .
Measurement of Cold Detection Thresholds (CDT) 48 hours after cream application The tests for thermal sensation will all be performed using a PATHWAY ATS (Medoc Ltd, Israel) thermal sensory testing device. A thermode stimulator of 3x3 cm will be placed on the treated/placebo areas and kept in place by means of Velcro tape. During the first 8 seconds, the temperature decreases 1°C per second from a starting temperature of 32°C until the subject perceives a temperature change (cold sensation) and presses a button that will terminate the measurement and return the temperature to baseline at a rate of 5°C /s. A cut-off temperature of 0°C will be used.
Measurement of Heat Pain Thresholds (HPT) 48 hours after cream application The tests for thermal sensation will all be performed using the same PATHWAY ATS thermal sensory testing device as above. The stimulations are again applied on the treated/placebo areas. During the first 8 seconds, the temperature raises 1°C per second from a starting temperature of 32°C until the subject detects a painful sensation and presses a button that will terminate the measurement and return the temperature to baseline at a rate of 5°C /s. A cut-off temperature of 52°C will be used.
Trial Locations
- Locations (1)
Aalborg University
🇩🇰Aalborg, Denmark