Pain, BurningNCT06185582
Repetitive Applications of Pruritogens and Effects of a Cutaneous-induced Pain Stimulation on Nonhistaminergic Itch Perception
A study testing Cowhage in people with Pain, Burning and Capsaicin, run by Aalborg University at 1 site in Denmark.
Trial summary
In This experiment, the investigators would like to test following hypotheses: the pain stimulation applied at the same time of a pruriceptive stimulus will decrease the itch perception. Read more about this study
- Who is it for?
- Ages 18 to 60 yearsHealthy volunteers can take part
- Conditions the study is for
- Pain, Burning, Capsaicin
- What is being tested?
- Cowhage
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 30 participants
- Where
- 1 siteDenmark
- Study dates
- 15 Dec 2023to 30 Jun 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 60 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Healthy men and women
- 18-60 years
- Speak and understand English
Who cannot join
- Pregnancy or lactation
- Drug addiction defined as any use of cannabis, opioids, or other addictive drugs
- Previous or current history of neurological (e.g. neuropathy), immunological (e.g. asthma, immune deficiencies, arthritis) musculoskeletal (e.g. muscular pain in the upper extremities,), cardiac disorder, or mental illnesses that may affect the results
- 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 (e.g. atopic dermatitis, pruritus nodularis, eczema, psoriasis)
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- Moles, scars, or tattoos in the area to be treated or tested.
- Consumption of alcohol or painkillers 24 hours before the study days and between these
- Acute or chronic pain
- Participation in other trials within one week of study entry (four weeks in the case of pharmaceutical trials)
Trial locations and contacts
1 site in 1 country.
About this study
In This experiment, the investigators would like to test following hypotheses:
the pain stimulation applied at the same time of a pruriceptive stimulus will decrease the itch perception. Moreover, also the effect of the cutaneous pain stimulus location (same forearm of the pruriceptive stimulus versus the opposite forearm) on histaminergic and non-histaminergic itch will be investigated.
Read the detailed description
The phenomenon that pain inhibits pain is a well-known mechanism, but it is not known if pain is inhibiting itch. In this context, the aim of this project is to investigate the extent to which thermal or neurogenic short cutaneous pain can affect the itch perception. In particular, the project aims to understand any differences in itch perception when the painful stimulation is applied on the same forearm versus the opposite forearm. The hypothesis is that by applying a painful stimulus at the same time of an itchy stimulus, the itch sensitivity will decrease; probably due to an inhibitory process conducted by interneurons (Bhlbb5 interneuron) at central level.
- Conditions
- Pain, Burning, Capsaicin
- Being tested
- Cowhage
- Medical subject headings
- Pain
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
CowhageOther
25 spicules will be inserted in the center of the predefined skin area on the mandibular area. The spicules will be gently rubbed for 15-20 seconds in circular motion to facilitate epidermal penetration.
| Study group | Role | What they receive |
|---|---|---|
| Pain | Experimental | A thermode stimulator of 3x3 cm will be placed on the areas and kept in place by means of Velcro tape. The temperature raises 1°C per second from a starting temperature of 32°C until itch reach or 46.5 °C. This temperature will be maintained for 2 minutes. Then the temperature will return to baseline temperature at a rate of 5°C /s. Receives: Other: Cowhage |
| Capsaicin | Experimental | Capsaicin patches (dosage form: transdermal patch 8% Qutenza, Astellas) will be applied on one squared area (4x4 cm2). The patch will be left in place for 20 minutes after which it will be removed. Receives: Other: Cowhage |
What is being measured
The primary outcome is the main question the study is designed to answer.
Assessment of itch intensity using a VAS scale
Immediately following the itch provocations, participants will be instructed to rate the itch intensity for 10 minutes using a digital visual analogue scale (VAS; eVAS Software: Aalborg, University, Denmark), on a tablet. The scale will be measured from 0 to 100, where 0 represents 'no itch' and 100 'worst itch imaginable'.
Measured: 1 minute post itch provocation
Assessment of pain intensity using a VAS scale
Immediately following the itch provocations, participants will be instructed to rate the pain intensity for 10 minutes using a digital visual analogue scale (VAS; eVAS Software: Aalborg, University, Denmark), on a tablet. The scale will be measured from 0 to 100, where 0 represents 'no pain' and 100 'worst pain imaginable'.
Measured: 1 minute post itch provocation
Retrospective rating of the pain perceived on a NRS
After 10 minutes of pruritogens application, a retrospective rating of the pain perceived from the thermal pain/capsaicin will be provided by the subject using a numeral rating scale (NRS)
Measured: 10 minutes post itch provocation
Secondary outcomes (2)
Alloknesis
Alloknesis sensation is measured using a standardized sensory brush (SENSELab Brush-05, Somedic AB, Hörby, Sweden) exerting a force of 200 to 400 mN.
Measured: 12 minutes post itch provocation
Mechanically evoked itch
Mechanically evoked itch is measured using three von Frey filaments of 4.08, 4.16 and 4.31 (1.0, 1.4, 2.0 g, respectively) (North Coast Medical, Gilroy, CA). The center of the skin area is stimulated by 3 pricks, repeated 3 times in short succession. After a total of 9 stimulations, the participants will report the itch elicited on a numerical rating scale (NRS) from 0 to 10 (0 = "no itch"; 10 = "worst imaginable itch").
Measured: 15 minutes post itch provocation
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Dec 2023
- Study start15 Dec 2023
- Primary completion31 Dec 2024
- Study completion30 Jun 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Pain, BurningStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Single group
- Model description
- The sub-project takes place over three sessions on three consecutive days. The participants will randomly receive two pruritogens and two pain stimulations (heat or capsaicin) in the same and in the opposite arm.
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 30 participants (actual)
Sponsor and investigators
- Lead sponsor
- Aalborg University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Silvia Lo Vecchio, Aalborg University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06185582
- Sponsor's protocol ID
- N-20210046 2nd project
- Status last verified
- Nov 2026
- First submitted
- 20 Nov 2023
- Last updated
- 6 Nov 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 6 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Repetitive Applications of Pruritogens and Effects of a Cutaneous-induced Pain Stimulation on Nonhistaminergic Itch Perception
- ClinicalTrials.gov ID
- NCT06185582
- Acronym / sponsor ID
- N-20210046 2nd project
- Conditions
- Pain, Burning, Capsaicin
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 30 participants (actual)
- Lead sponsor
- Aalborg UniversityUniversity, hospital or other
- Study start
- 15 Dec 2023 (actual)
- Primary completion
- 31 Dec 2024 (actual)
- Study completion
- 30 Jun 2025 (actual)
- First posted
- 29 Dec 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
In This experiment, the investigators would like to test following hypotheses:
the pain stimulation applied at the same time of a pruriceptive stimulus will decrease the itch perception. Moreover, also the effect of the cutaneous pain stimulus location (same forearm of the pruriceptive stimulus versus the opposite forearm) on histaminergic and non-histaminergic itch will be investigated.
Detailed description
The phenomenon that pain inhibits pain is a well-known mechanism, but it is not known if pain is inhibiting itch. In this context, the aim of this project is to investigate the extent to which thermal or neurogenic short cutaneous pain can affect the itch perception. In particular, the project aims to understand any differences in itch perception when the painful stimulation is applied on the same forearm versus the opposite forearm. The hypothesis is that by applying a painful stimulus at the same time of an itchy stimulus, the itch sensitivity will decrease; probably due to an inhibitory process conducted by interneurons (Bhlbb5 interneuron) at central level.
Study design
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Single group
- Masking
- Single blind (participant)
- Number of arms
- 2
- Model description
- The sub-project takes place over three sessions on three consecutive days. The participants will randomly receive two pruritogens and two pain stimulations (heat or capsaicin) in the same and in the opposite arm.
| Arm | Type | Receives |
|---|---|---|
| Pain | Experimental | Other: CowhageA thermode stimulator of 3x3 cm will be placed on the areas and kept in place by means of Velcro tape. The temperature raises 1°C per second from a starting temperature of 32°C until itch reach or 46.5 °C. This temperature will be maintained for 2 minutes. Then the temperature will return to baseline temperature at a rate of 5°C /s. |
| Capsaicin | Experimental | Other: CowhageCapsaicin patches (dosage form: transdermal patch 8% Qutenza, Astellas) will be applied on one squared area (4x4 cm2). The patch will be left in place for 20 minutes after which it will be removed. |
Who may qualify
- Ages
- 18 to 60 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- Healthy men and women
- 18-60 years
- Speak and understand English
Key exclusion criteria (10 listed)
- Pregnancy or lactation
- Drug addiction defined as any use of cannabis, opioids, or other addictive drugs
- Previous or current history of neurological (e.g. neuropathy), immunological (e.g. asthma, immune deficiencies, arthritis) musculoskeletal (e.g. muscular pain in the upper extremities,), cardiac disorder, or mental illnesses that may affect the results
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Cowhage25 spicules will be inserted in the center of the predefined skin area on the mandibular area. The spicules will be gently rubbed for 15-20 seconds in circular motion to facilitate epidermal penetration. | Other | Capsaicin, Pain |
Primary outcome
Assessment of itch intensity using a VAS scale
Time frame: 1 minute post itch provocation
Immediately following the itch provocations, participants will be instructed to rate the itch intensity for 10 minutes using a digital visual analogue scale (VAS; eVAS Software: Aalborg, University, Denmark), on a tablet. The scale will be measured from 0 to 100, where 0 represents 'no itch' and 100 'worst itch imaginable'.
Assessment of pain intensity using a VAS scale
Time frame: 1 minute post itch provocation
Immediately following the itch provocations, participants will be instructed to rate the pain intensity for 10 minutes using a digital visual analogue scale (VAS; eVAS Software: Aalborg, University, Denmark), on a tablet. The scale will be measured from 0 to 100, where 0 represents 'no pain' and 100 'worst pain imaginable'.
Retrospective rating of the pain perceived on a NRS
Time frame: 10 minutes post itch provocation
After 10 minutes of pruritogens application, a retrospective rating of the pain perceived from the thermal pain/capsaicin will be provided by the subject using a numeral rating scale (NRS)
2 secondary outcomes
Alloknesis
Time frame: 12 minutes post itch provocation
Mechanically evoked itch
Time frame: 15 minutes post itch provocation
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Nov 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Cowhage in people with Pain, Burning and Capsaicin, run by Aalborg University at 1 site in Denmark.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 6 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Denmark. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Assessment of itch intensity using a VAS scale (time frame: 1 minute post itch provocation). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 Nov 2026.