Itch Sensation Induced by Multiple Applications of Pruritogens (temporal Summation)

Aalborg University

Status: Enrolling

Conditions: Cowhage; Histamine

Treatments: Other: Cowhage; Other: Histamine

Study type: Interventional

Funder types: Other

Identifiers

NCT06328543

N-20210046 4th project

Details and patient eligibility

About

In This experiment, the investigators would like to design a new itch model based on the temporal summation of pruritic stimuli. The hypothesis behind this study (temporal summation) is that two overlapped applications of pruritogens will result in a higher itch sensation compared with a single application.

Full description

Chronic itch affects approximately a fifth of the global population and is associated with substantial negative consequences for the affected individuals. Furthermore, there is a lack of efficient treatment options for chronic itch. In order to mimic a clinical itch condition as presented in patients, the aim of the project is to investigate a new itch model based on the multiple applications of pruritogens (temporal summation). In particular, the purpose is to evaluate if a single application of cowhage/histamine (non-histaminergic and histaminergic itch, respectively) results in a lower itch sensation compared with two overlapped applications of the pruritogens on the same area.

Enrollment: 26 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 Englis

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)

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Single Group Assignment

Masking: Single Blind

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26 participants in 2 patient groups

1st pruritogen

Experimental group

Description:

The subproject is conducted in 1 session (approx. 3 hours in total) divided into two parts. In the first part, 3 test areas (3x3 cm) will be selected on one forearm of the subject. The 3 areas will be randomly treated with 1 application of cowhage, 2 applications of cowhage (the second application will be conducted 90 seconds after the first one in the same area), and 2 applications of cowhage (the second application will be conducted 180 seconds after the first one in the same area). Itch will be monitored using a VAS (visual analog scale) for 15 min in each session. After the removal of cowhage, FLPI, alloknesis, and mechanically evoked itch will be measured.

Treatment:

Other: Histamine

2nd pruritogen

Experimental group

Description:

The second part will be conducted 20 minutes after the first part, and the procedure will be the same, but using histamine instead of cowhage. The two parts will be randomized between subjects.

Treatment:

Other: Cowhage