Light-emitting diode photobiomodulation is the newest category of nonthermal light therapies to find its way to the dermatologic armamentarium. In this article, we briefly review the literature on the development of this technology, its evolution within esthetic and medical dermatology, and provide practical and technical considerations for use in various conditions. This article also focuses on the specific cell-signaling pathways involved and how the mechanisms at play can be put to use to treat a variety of cutaneous problems as a stand-alone application and/or complementary treatment modality or as one of the best photodynamic therapy light source.

In the last decade, it has been proposed that the sun's IR-A wavelengths might be deleterious to human skin and that sunscreens, in addition to their desired effect to protect against UV-B and UV-A, should also protect against IR-A (and perhaps even visible light). Several studies showed that NIR may damage skin collagen content via an increase inMMP-1 activity in the same manner as is known for UVR. Unfortunately, the artificial NIR light sources used in such studies were not representative of the solar irradiance. Yet, little has been said about the other side of the coin. This article will focus on key information suggesting that IR-A may be more beneficial than deleterious when the skin is exposed to the appropriate irradiance/dose of IR-A radiation similar to daily sun exposure received by people in real life.IR-A might even precondition the skin--a process called photo prevention--from an evolutionary standpoint since exposure to early morning IR-A wavelengths in sunlight may ready the skin for the coming mid-day deleterious UVR. Consequently IR-A appears to be the solution, not the problem. It does more good than bad for the skin. It is essentially a question of intensity and how we can learn from the sun. © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Background: Jet injection can be defined as a needle-free drug delivery method in which a high-speed stream of fluid impacts the skin and delivers a drug. Despite 75 years of existence, it never reached its full potential as a strategic tool to deliver medications through the skin. Objective: The aim of this review was to evaluate and summarize the evolution of jet injection intradermal drug delivery method including technological advancements and new indications for use. Methods: A review of the literature was performed with no limits placed on publication date. Results: Needleless injectors not only reduce pain during drug delivery but also confine the drug more evenly in the dermis. Understanding skin properties of the injection site is a key factor to obtain optimal results as well as setting the right parameters of the jet injector. Until the advent of disposable jet injectors/cartridges, autoclaving of the injector remains the only reliable method to eliminate the risk of infection. Needle-free intradermal injection using corticosteroids and/or local anesthetics is well documented with promising indications being developed. Limitations: Limitations of the review include low-quality evidence, small sample sizes, varying treatment parameters, and publication bias. Conclusion: New developments may help reconsider the use of jet injection technology. Future studies should focus on measurable optimized parameters to insure a safe and effective outcome.

Background and Objectives: As photoprotection with traditional sunscreen presents some limitations, the use of non‐traditional treatments to increase skin resistance to ultraviolet (UV) induced damage would prove particularly appealing. The purpose of this pilot study was to test the potential of non‐thermal pulsed light‐emitting diode (LED) treatments (660 nm) prior to UV exposure in the induction of a state of cellular resistance against UV‐induced erythema.Study Design/Materials and Methods: Thirteen healthy subjects and two patients with polymorphous light eruption (PLE) were exposed to 5, 6, or 10 LED treatments (660 nm) on an EXPERIMENTAL anterior thigh region. Individual baseline minimal erythema doses (MED) were then determined. UV radiation was thereafter performed on the LED EXPERIMENTAL and CONTROL anterior thigh areas. Finally, 24 hours post‐UV irradiation, LED pre‐treated MED responses were compared to the non‐treated sites.Results: Reduction of erythema was considered significant when erythema was reduced by >50% on the LED‐treated side as opposed to CONTROL side. A significant LED treatment reduction in UV‐B induced erythema reaction was observed in at least one occasion in 85% of subjects, including patients suffering from PLE. Moreover, there was evidence of a dose‐related pattern in results. Finally, a sun protection factor SPF‐15‐like effect and a reduction in post‐inflammatory hyperpigmentation were observed on the LED pre‐treated side.Conclusions: Results suggest that LED based therapy prior to UV exposure provided significant protection against UV‐B induced erythema. The induction of cellular resistance to UV insults may possibly be explained by the induction of a state a natural resistance to the skin via specific cell signaling pathways and without the drawbacks and limitations of traditional sunscreens. These results represent an encouraging step towards expanding the potential applications of LED therapy and could be useful in the treatment of patients with anomalous reactions to sunlight. Lesers Surg. Med. 40:106–112, 2008.