Pain, Itch
Conditions
Brief summary
The experiment consists of three experimental sessions conducted on three consecutive days. In all experimental sessions, the participant will fill in a series of questionnaires about how you perceive itch and pain, and about some traits of your personality, such as depression, anxiety and stress. In the first session, we will mark six test areas in your face (three on each side on jaw, cheek, and temple, respectively). Thent a series of measure-ments in each test area will be conducted:measurement of the blood flow in the skin and sensitivity tests to pressure, pinprick and stroke with a brush. In the second session, histamine will be applied in one side of the face. On the other side, cowhage spicules will be applied. After 10 minutes, all the tests will be conducted again. The third session will be identical to the second. However, instead of histamine and spicules, patches containing capsaicin will be applied. In the other side, we will apply patches with placebo (i.e., a non-active patch). After 20 minutes all the tests will be conducted again.
Interventions
OTHERHistamine
To deliver histamine, standard allergy skin prick test (SPT) lancets are applied
OTHERCowhage
The spicules will be manually inserted. Approximately 30-35 spicules are gently rubbed into a 1 cm diameter skin area on the forearm/face
OTHERCapsaicin 8% Patch
Capsaicin patches (dosage form: transdermal patch 8% Qutenza, Astellas) will be applied on 3 squared areas in the face.
OTHERDemo patch
Placebo patch (demo patch, containing the same formulation as the active treatment with the exception of capsaicin) will be applied on 3 squared areas in the face.
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 drugs * Previous or current history of neurological, immunological, musculoskeletal, cardiac disorder or psychiatric diagnoses that may affect the results (e.g., neuropathy, muscular pain in the upper extremities, anxiety, depression, schizophrenia, etc.) * Moles, wounds, scars, or tattoos in the area to be treated or tested * Current use of medications that may affect the trial such as antihistamines and pain killers * Skin diseases * Consumption of alcohol or painkillers 24 hours before the study days and between these * Acute or chronic pain and itch * Participation in other trials within 1 week of study entry (4 weeks in the case of pharmaceutical studies) * Contraindications to capsaicin, including intolerance to chili or burns or wounds at the application site * The subject is assessed as unable to engage in the necessary cooperation required by the study
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Measuring pain by computerized Visual Analog Scale Scoring | Baseline | 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. |
| Measuring itch by computerized Visual Analog Scale Scoring | Baseline | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Mechanically evoked itch (MEI) | Baseline | MEI is measured by using mildly pruritic, non-painful von Frey nylon filaments of a predetermined intensity (generally 5-30 miliNewton of force). |
| Mechanical Pain Thresholds (MPT) | Baseline | This test is conducted using a pinprick set. The set consists of 7 needles each with a diameter of 0.6 mm and different force applications: 8, 16, 32, 64, 128, 256, and 512 mN. |
| Mechanical Pain Sensitivity (MPS) | Baseline | This test is conducted with the same pinprick set used to test the MPT. |
| Cold Detection Thresholds (CDT) | Baseline | The tests of thermal sensation will all be conducted using a PATHWAY ATS (Medoc Ltd, Israel) thermal sensory testing device |
| Warm Detection Thresholds (WDT) | Baseline | The tests of thermal sensation will all be conducted using a PATHWAY ATS (Medoc Ltd, Israel) thermal sensory testing device |
| Cold Pain Thresholds (CPT) | Baseline | The tests of thermal sensation will all be conducted using a PATHWAY ATS (Medoc Ltd, Israel) thermal sensory testing device |
| Heat Pain Thresholds (HPT) | Baseline | The tests of thermal sensation will all be conducted using a PATHWAY ATS (Medoc Ltd, Israel) thermal sensory testing device |
| Superficial blood perfusion | Baseline | Superficial blood perfusion (SBP) is measured by a Speckle contrast imager |
| Pain Catastrophizing Scale (PCS). | Baseline | The PCS assesses negative and exaggerated coping concerning anticipated or experienced painful stimuli. Thirteen items have to be answered on a 5-point Likert-type scale ranging from 0 (Not at all) to 4 (all the time). |
| Itch Catastrophizing Scale (ICS). | Baseline | The ICS assesses negative and exaggerated coping concerning anticipated or experienced itchy stimuli. Thirteen items have to be answered on a 5-point Likert-type scale ranging from 0 (Not at all) to 4 (all the time). |
| Learned Helplessness Scale (LHS) | Baseline | The questionnaire consists of 20 items, and the participant's response to each item is rated on a 4-point Likert scale ranging from strongly agree (1) to strongly disagree (4). |
| Depression, Anxiety, Stress Scale (DASS-21) | Baseline | The questionnaire measures the magnitude of depression, anxiety, and stress. Each of these three subscales consists of 7 questions answered using a 0-3 Likert scale, with 0 meaning it did not apply to me, and 3 meaning it applied to me very much |
| Reinforcement Sensitivity Theory - Personality Questionnaire (RST-PQ). | Baseline | The RST-PQ contains in total, 65 items must be answered on a 4-point Likert-type scale |
| Difficulties in Emotion Regulation Scale Short Form (DERS-SF) | Baseline | The questionnaire is an 18-item measure used to identify emotional regulation issues in adults. Participants rate each item on a 5-point Likert scale (from 1 to 5). |
| Emotion Regulation Questionnaire (ERQ | Baseline | This questionnaire is designed to assess individual differences in the habitual use of two emotion regulation strategies: cognitive reappraisal and expressive suppression. Respondents answer each item on a 7-point Likert-type scale ranging from 1 (strongly disagree) to 7 (strongly agree), where 4 means (neutral). |
| Pain to Supra-threshold Heat Stimuli (STHS) | Baseline | The tests of thermal sensation will all be conducted using a PATHWAY ATS (Medoc Ltd, Israel) thermal sensory testing device |
| Alloknesis | Baseline | Measured using a standardized sensory brush exerting a force of 200 to 400 mN. |
Countries
Denmark
Contacts
Primary ContactSilvia Lo Vecchio
Outcome results
None listed