Mechanisms Underlying the Nocibo Effect of Contagious Itch. in Both Histaminergic and Nonhistaminergic Itch

Aalborg University

Status: Not yet enrolling

Conditions: ITCH

Treatments: Other: Placebo; Other: Histamine; Other: Cowhage (Mucuna Pruriens)

Study type: Interventional

Funder types: Other

Identifiers

NCT07255092

N-20250017 Project 3

Details and patient eligibility

About

The study consists of one experimental session of approximately 1½ hours. 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. Afterwards, three areas will be selected on each forearm of the subjects.

Two areas will be treated with histamine, two with cowhage, and two with vehicle. One application of each substance will be conducted including the contagious itch component. During the 10 minutes of the application of the pruritogens, itch and pain will be continuously monitored using a VAS scale.

Enrollment: 30 estimated patients

Sex: All

Ages: 18 to 60 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• 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

Trial design

Primary purpose: Basic Science

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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30 participants in 1 patient group

Contagious itch

Experimental group

Description:

A contagious itch will be induced by a video (without audio) showing people scratching.

Treatment:

Other: Cowhage (Mucuna Pruriens)

Other: Histamine

Other: Placebo