In vivo and in vitro analysis of low level light therapy: a useful therapeutic approach for sensitive skin

Abstract

Sensitive skin is a relatively common dermatologic condition and no optimal treatments have been established so far. Low-level laser/light therapy (LLLT) has been used for its biostimulative effect in various clinical settings. The purpose of this study was to investigate whether low-level laser/light therapy can improve sensitive skin clinically and to evaluate the effects of LLLT on skin in vitro. Twenty-eight patients complaining of sensitive skin were treated with low-level polarized light, and clinical results were evaluated using subjective and objective method. To investigate possible working mechanism of LLLT on skin, cultured human keratinocytes pretreated with nontoxic concentration of sodium lauryl sulfate (SLS) were used. Cytokines released from irritated keratinocytes after LLLT were analyzed. All patients showed subjective and objective improvement after treatment. No adverse effects were reported. The average number of LLLT sessions required to achieve clinical improvement was 9.9, and cumulative dose of LLLT was 71.3 J/cm(2) on the average. Erythema index decreased significantly after LLLT treatment (p = 0.017). In vitro assay showed that LLLT significantly reduced the release of VEGF from SLS-pretreated keratinocytes (p = 0.021). Our results suggest that LLLT could be a useful and safe treatment modality for sensitive skin, and modification of inflammatory cytokines released from irritated keratinocytes may be considered as one of plausible mechanisms in sensitive skin treated with LLLT.

Proposed Mechanisms of Photobiomodulation or Low-Level Light Therapy

“…The anti-inflammatory effect of light in low intensity was reported on patients with arthritis, acrodermatitis continua, sensitive and erythematous skin, for instance [136]. With the same basic mechanism of action, which is the light absorption by mitochondrial chromophores, mainly Cox, the consequences of PBM are various, depending on the parameters used, on the signaling pathways that are activated and on the treated tissue.…”

Photobiomodulation devices for hair regrowth and wound healing: a therapy full of promise but a literature full of confusion

“…We have reason to believe that light reception may involve the much-vaunted but still inconclusive cytochrome c oxidase (29), nitrosated proteins regulating nitric oxide (NO) bioactivity (30,31), the circadian rhythm-regulatoring flavoprotein cryptochrome (32) and the more recently considered opsin family of photoreceptors (20,(33)(34)(35)(36). Understanding of the field is further complicated, as effector pathways could also be triggered indirectly, for example by ROS with the activation of ERK or production of growth factors and cytokines (37)(38)(39)(40).…”

Pathophysiology and management of sensitive skin: position paper from the special interest group on sensitive skin of the International Forum for the Study of Itch (IFSI)

“…TRPV1 is an important ion channel on epidermal nerve fibres which mediates neurogenic inflammation. 79 Alternatively, low level laser/light therapy 80,81 and botanical anti-inflammatories 82 have shown beneficial effects in sensitive skin. 77 Substances addressing the TRPV1, such as its agonist capsaicin, have a less beneficial side-effect profile and may worsen neurogenic inflammation and sensitive skin.…”

“…78 The association of inhibitors of neurogenic inflammation might be valuable. 79 Alternatively, low level laser/light therapy 80,81 and botanical anti-inflammatories 82 have shown beneficial effects in sensitive skin.…”