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

Medical University of Graz

Status: Completed

Conditions: Healthy Volunteers

Treatments: Device: Low Level Light Therapy; Device: Sham Controll

Study type: Interventional

Funder types: Other

Identifiers

NCT05369338

33-431 ex 21/22

Details and patient eligibility

About

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.

Full 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.

Enrollment: 17 patients

Sex: All

Ages: 18 to 60 years old

Volunteers: Accepts Healthy Volunteers

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

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Triple Blind

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17 participants in 2 patient groups

Low Level Light Therapy

Experimental group

Description:

The application of LLL is applied for 12 minutes using Repuls 7 (Repuls Lichtmedizintechnik GmbH, Vienna). This is a class IIb medical device. It applies pulsed red light of a frequency of 640nm. The intensity is 175 mWcm-2, which corresponds to a power density of 4,100 mW. The pulse frequency is set to 2.5 hz. The device is positioned 7cm from the skin using a distance ring.

Treatment:

Device: Low Level Light Therapy

Sham controll

Sham Comparator group

Description:

The application of LLL is applied for 12 minutes using Repuls 7 (Repuls Lichtmedizintechnik GmbH, Vienna). This is a class IIb medical device. It applies pulsed red light of a frequency of 640nm. The intensity is 175 mWcm-2, which corresponds to a power density of 4,100 mW. The pulse frequency is set to 2.5 hz. The device is positioned 7cm from the skin using a distance ring. The sham treatment is performed with the same device and the same distance ring without activating it.

Treatment:

Device: Sham Controll