Clinical trial NCT05369338: The Effect of Low Level Light Therapy on Histamine- and Mucuna Pruriens-induced Pruritus in Healthy Volunteers
Official title: The Effect of Low Level Light Therapy on Histamine- and Mucuna Pruriens-induced Pruritus in Healthy Volunteers: A Prospective, Double-blind, Randomised Sham-controlled Pilot Study
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Healthy Volunteers
Lead sponsor: Medical University of Graz
Sponsor class: OTHER
First posted: 2022-05-11
Enrollment: 17
Sex: ALL
Minimum age (years): 18
Maximum age (years): 60
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Intervention model description: Prospective, double-blind, randomised, sham-controlled
Primary purpose: BASIC_SCIENCE

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.

Eligibility criteria: 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

Primary outcomes:
measure: Pruritus Intensity
timeFrame: 2 minutes
Secondary outcomes:
measure: Neurogenic inflammation
timeFrame: 10 minutes
measure: Alloknesia
timeFrame: 10 minutes
measure: Hyperknesia
timeFrame: 10 minutes
Other outcomes:
Locations:
city: Graz
country: Austria
facility: Medical university of Graz
Study officials:
References: