Volume 21, No.2, Oct. 2014 The Gulf Journal of Dermatology and Venereology 1 REVIEW ARTICLE Low Level Laser Therapy in Dermatology Fatma Abd Al Salam, MD, Wafaa Affy, MD Al-Azhar University , Cairo, Egypt Laser is an acronym for Light Amplifcation by Stimulated Emission of Radiation. LASER COMPONENTS All lasers contain 3 primary components to oper- ate: 1-Active medium 2- Excitation mechanism and 3- The optical resonator 1- Active medium: It is a collection of atoms, molecules, or ions which absorb energy from an outside source and generate laser light through atomic processes. The active medium may be solid, liquid or gas. 2- Excitation Mechanism: It is the input energy device, which could be an intense light source, an electrical current through an active gas, or in the case of dye lasers, light from another laser. 3- Optical Resonator: Consists of 2 specially designed mirrors, dia- gramatically opposed to each other. The high re- fectance mirror refects 100% of the light which strikes it, while the other mirror (partially trans- missive mirror) refects less than 100% of the light which strikes it. The small fraction of light which passes through the partially transmissive mirror is the beam output. 1 The therapeutic action of laser energy is based on the unique properties of laser light and laser tissue interaction. LASER PROPERTIES 1. Monochromatic: The emitted light is of sin- gle, discrete wavelength that can be absorbed by specifc targets or chromophores. 2. Coherence: Laser light traveling in phase with respect to both time and space. 3. Collimation: Emission of a narrow, intense beam of light in parallel fashion to achieve BACKGROUND Low-level laser therapy (LLLT) refers to the use of a red-beam or near-infrared laser with a wave-length between 600 and 1000 nanometers and power from 5 to 500 millwatts. Other names for the therapy include low-power laser, soft laser, cold laser, biostimulation laser and therapeutic laser. As high-power lasers ablate tissue, low-power lasers stimulate it, en- couraging the cells to function. The laser photons are absorbed by mitochondrial chromophores. (cytochrome-c oxidase) stimulating oxidative phosphorylation to increase ATP production and reduce oxidative stress. This effects lead to improved tissue repair, reduces infammation and reduces pain. LLLT has benefcial effects on many dermatologic disorders including wound healing, hypertrophic scars and burns, herpes simplex, acne and acne scars; wrinkles, vitiligo and psoriasis. LLLT is safe, simple, non invasive, painless, drugless therapy, easy to apply, with no reported side effect. Correspondence: Dr. Fatma Abd Al Salam, Al-Azhar University , Cairo, Egypt E-mail: dr.fatmaabdalsalam@yahoo.com