The Effect of Low Level Light Therapy on Histamine- and Mucuna Pruriens-induced Pruritus in Healthy Volunteers

Not Applicable

Completed

• Conditions: Healthy Volunteers

• Registration Number: NCT05369338
• Lead Sponsor: Medical University of Graz

Brief Summary

This is a prospective, double-blind, randomised, sham-controlled study whose primary aim is to test whether LLLT changes the intensity of itch after histamine application in healthy volunteers compared to sham application.

Detailed Description

Rationale and relevance of the study

Low-level light therapy (LLLT) is a method of photobiomodulation that involves the clinical application of light with wavelengths typically in the range of 600 to 1100 nm and with a typical power density of 5 mWcm² to 5 Wcm².

Clinical studies have demonstrated positive effects of LLLT on pain processing, which is attributed to a reduction in neurogenic inflammation and associated neuronal sensitisation. This has been proven by testing for hyperaesthesia or allodynia. In the course of neurogenic inflammation, histamine liberation also occurs, which can be associated with itching. Chronic itching is also frequently associated with somatosensory abnormalities in analogy to chronic pain. Itch-associated dysaesthesias, such as mechanical allocnesia and hyperknesia, can be seen as evidence of neuronal sensitisation in pruritus patients.

Oliviera et al. were able to demonstrate an antipruritic effect of LLLT in a case observation of five burn victims. By irradiating with laser, whose photobiomodulative mechanisms are similar to the mechanisms of LLL therapy, this effect was also investigated in lichen planus patients. The effect of LLL on pruritus can be demonstrated in the case observation of five burn victims.

Itch models can be divided into histamine-induced and non-histamine-induced. To date, there has been no structured investigation of the antipruritic effect of LLL, nor is it clear to what extent the itch-inducing mechanism has an influence on the suspected efficacy of LLL.

Study Timeline

• Study Start: 2022-05-06
• Study First Submitted: 2022-05-06
• Study First Submitted QC: 2022-05-06
• Study First Posted: 2022-05-11
• Status Verified: 2022-08
• Primary Completion: 2022-08-04
• Study Completion: 2022-08-04
• Last Update Submitted: 2022-08-12
• Last Update Posted: 2022-08-15

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 17

Inclusion Criteria

• Written informed consent of the participant
• Healthy test persons aged 18-60
• For female volunteers, negative pregnancy test

Exclusion Criteria

• known allergy or hypersensitivity to histamine or the Mucuna pruriens
• history of skin diseases
• tattoos in the test area
• neoplasia in the test area
• pacemaker
• pregnancy
• epilepsy
• piercings
• fever
• local acute infection, skin inflammation/rashes

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Primary Outcome Measures

Name	Time	Method
Pruritus Intensity	2 minutes	Histaminergic itch is determined using a visual analogue scale (0-100) The non-histaminergic itch is determined by means of a visual analogue scale (0-100).

Secondary Outcome Measures

Name	Time	Method
Alloknesia	10 minutes	an area of alloknesia will be tested in the histaminergic itch model using cotton swabs.; an area of alloknesia is tested in the non-histaminergic itch model using cotton swabs.
Neurogenic inflammation	10 minutes	The neurogenic inflammation of histaminergic itch is determined by recording the flare area and measuring the skin temperature.; The neurogenic inflammation of non-histaminergic itch is determined by recording the flare area and measuring the skin temperature.
Hyperknesia	10 minutes	a hyperkneesia area is tested in the histaminergic itch model using a von Frey filament.; a hyperkneesia area is tested in the non-histaminergic itch model using a von Frey filament.

Trial Locations

Locations (1)

Medical university of Graz; 🇦🇹 Graz, Austria