Clinical trial NCT06185582: Repetitive Applications of Pruritogens and Effects of a Cutaneous-induced Pain Stimulation on Nonhistaminergic Itch Perception
Official title: Repetitive Applications of Pruritogens and Effects of a Cutaneous-induced Pain Stimulation on Nonhistaminergic Itch Perception
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: Pain, Burning
Capsaicin
Lead sponsor: Aalborg University
Sponsor class: OTHER
First posted: 2023-12-29
Enrollment: 30
Sex: ALL
Minimum age (years): 18
Maximum age (years): 60
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: NON_RANDOMIZED
Intervention model: SINGLE_GROUP
Intervention 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.
Primary purpose: BASIC_SCIENCE

Brief 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. 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.

Eligibility criteria: 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 (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)
* 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)

Primary outcomes:
measure: Assessment of itch intensity using a VAS scale
timeFrame: 1 minute post itch provocation
measure: Assessment of pain intensity using a VAS scale
timeFrame: 1 minute post itch provocation
measure: Retrospective rating of the pain perceived on a NRS
timeFrame: 10 minutes post itch provocation
Secondary outcomes:
measure: Alloknesis
timeFrame: 12 minutes post itch provocation
measure: Mechanically evoked itch
timeFrame: 15 minutes post itch provocation
Other outcomes:
Locations:
city: Aalborg
country: Denmark
facility: Aalborg University
Study officials:
References: