‘Blue’ and red light

Light exposure has long been used as a short term treatment for acne. Recently, visible light has been successfully employed to treat mild to moderate acne (phototherapy or deep penetrating light therapy) – in particular intense violet light (405-420 nm) generated by purpose-built fluorescent lighting, dichroic bulbs, LEDs or lasers. Used twice weekly, this has been shown to reduce the number of acne lesions by about 64%^[50] and is even more effective when applied daily. The mechanism appears to be that a porphyrin (Coproporphyrin III) produced within P. acnes generates free radicals when irradiated by 420 nm and shorter wavelengths of light.^[51] Particularly when applied over several days, these free radicals ultimately kill the bacteria.^[52] Since porphyrins are not otherwise present in skin, and no UV light is employed, it appears to be safe, and has been licensed by the U.S. FDA.^[53][54]

Dermabrasion is a cosmetic medical procedure in which the surface of the skin is removed by abrasion (sanding). It is used to remove sun-damaged skin and to remove or lessen scars and dark spots on the skin. The procedure is very painful and usually requires a general anaesthetic or “twilight anaesthesia”, in which the patient is still partly conscious^[49] Afterward, the skin is very red and raw-looking, and it takes several months for the skin to regrow and heal. Dermabrasion is useful for scar removal when the scar is raised above the surrounding skin, but is less effective with sunken scars.