Topographical Distribution of Itch and Pain Receptors

Aalborg University

Status

Enrolling

Conditions

Itch

Pain

Treatments

Other: Capsaicin 8% Patch

Other: Histamine

Other: Cowhage

Other: Demo patch

Study type

Interventional

Funder types

Other

Identifiers

NCT07122973

N-20250017 Project 4

Details and patient eligibility

About

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.

Enrollment

30 estimated patients

Sex

All

Ages

18 to 60 years old

Volunteers

Accepts Healthy Volunteers

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