Emerging therapies using lasers and high intensity light sources are some of the most exciting areas of research in the science of acne. Recent research has shown that both red light and blue light therapies may be helpful in inhibiting bacterial growth and encouraging the regeneration of healthy tissue. Lasers, of which there are several varieties, are used for both acne treatment and to correct the skin damage and scarring caused by acne. In this section, we overview these novel light-based treatments.
Light Based Therapies
LEDs are a Popular Light Source for Phototherapy
Research has indicated that high intensity light in the red spectrum (~630-740 nm) can decrease inflammation and stimulate the healing process by encouraging cellular proliferation and collagen remodeling. It appears that certain wavelengths of red light may be absorbed by important molecules involved in cellular metabolism, such as cytochrome oxidase. The stimulation of these molecules apparently induces cell growth, contributing to wound healing. In addition to use in cosmetic applications like acne treatment and photo-rejuvenation, red light therapy is also being experimentally applied after surgical procedures to accelerate healing. For acne-centered treatments, red light therapy is usually applied using either light emitting diodes (LEDs) or low intensity lasers as the light source. For post-surgical treatments, lasers are the more common technology. Red light therapy is often used in conjunction with blue light therapy or as part of a photo dynamic therapy (PDT) or intense pulsed light (IPL) system.
Blue Light Phototherapy Kills P. acnes Bacteria
Blue light therapy uses high intensity light in the blue spectrum (390-420 nm) to directly kill the primary bacteria involved in acne, P. acnes. Blue light is absorbed by a specific type of bacterial molecule called a porphyrin. Excitation of porphyrin with blue light causes it to release free radicals into the bacterium itself, killing the bacteria. Clinical research indicates that bi-weekly or daily blue light therapy can significantly reduce the number and severity of acne lesions. Blue light therapy is most commonly administered using LEDs as the light source, but lasers are also occasionally used. This type of therapy can be done both at home and in the dermatologist's office. In a clinical setting, blue light therapy is often combined with red light therapy and/or used as part of a PDT or IPL treatment.
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Since blue and red light phototherapy each operate in essentially the same way, it makes sense that they would be administered in a combined treatment. Performing blue and red light treatment at the same time combines the anti-bacterial activities of blue light therapy with the anti-inflammatory activity of red light therapy. Many of the research studies that demonstrated substantial improvements in acne symptoms utilized this combination.
Intense Pulsed Light (IPL) (Chromolite, AccelaWave, StarLux, IPL Quantum, LimeLight)
IPL has Many Applications - From Acne to Hair Removal
Intense Pulsed Light (IPL) systems are designed to administer rapid, high intensity pulses of light. The rapid pulsing prevents overheating of skin, thermal damage and discomfort of the patient. IPL systems are the most popular systems used to administer light therapy in the clinical environment. In general, they have a good safety record and demonstrable efficacy in the treatment of acne.
UV light (Tanning Beds, The Sun)
Many acne sufferer have noticed changes in their symptoms after exposure to ultra-violet light (200-400 nm), both from natural sunlight and tanning beds. In some cases, it appears that UV exposure improves symptoms, while in other cases it tends to exacerbate the problem. The research on the subject is relatively minimal and appears to be inconclusive. The general trend in the research indicates that UV exposure may temporarily increase levels of sebum production and may convert some non-comedogenic fatty acids into more comedogenic molecules. At the same time, sunlight and UV light are antibacterial themselves. In addition, mild sun exposure may even out skin tone, decreasing the appearance of acne lesions. Of course, any potential benefits must be weighed against the well established consequences of excessive UV exposure, such as premature aging of the skin and increased risk of melanoma.
Infra-Red (Titan)
Infrared Thermal Scan
Infra-red light therapies are used to warm the skin and the near-surface subcutaneous tissue. Infra-red treatments are often done in conjunction with other types of treatment.
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Photodynamic therapy combines a light based treatment (mostly blue or blue/red treatments) with a topical agent designed to increase the efficacy of the treatment. The most common form of PDT uses Aminolevulinic Acid (ALA), which increases the synthesis of porphyrin in P. acnes bacteria. The patient is then treated with blue light therapy, which causes the porphyrin to release toxic free radicals into the bacteria. The elevated levels of porphyrin make the blue light treatment more effective at killing the bacteria. PDT is also used in combination with other photo-sensitizing drugs and wavelengths of light for non-acne treatments, such as anti-cancer therapy.
Laser Based Therapies
595 nm Lasers are Absorbed by Hemoglobin
The pulsed dye laser produces a yellow laser (~595 nm), that is delivered in rapid pulses. The yellow laser is absorbed by hemoglobin, which is present in blood and tissue, and produces heat damage. Pulsed dye lasers are generally used to treat vascular lesions like Portwine stains, nevus flemmus, hemangiomas, other types of erythema. Erythema is redness caused by hyperemia (excess blood flow) of capillaries in the skin. Acne sufferers often develop erythematic scars, which are permanent red marks. Pulsed Dye Lasers have been shown to be very effective at eliminating these types of acne scars. Treatment is often used in conjunction with a topical retinoid, to accelerate the regeneration of the skin tissue and collagen matrix. Generally speaking, the PD Lasers are only for the resolution of acne scars and are not an effective treatment for acne itself.
Nd:YAG Laser (GentleYAG, PhotoSilk, CoolTouch, Affinity QS, Gemini, Excel, Genesis)
Nd:YAG Lasing Crystals
The Nd:YAG laser is a popular and versatile dermatological tool. Nd:YAG lasers are a class of laser that uses a crystal of Neodymium-Doped Yttrium Aluminium Garnet as the lasing medium. They are used extensively in medicine and other applications. In addition to acne treatment, they are used by dermatologists for the removal of hair and spider veins. Many systems used in dermatology offices have "Q-switch" capabilities, which allow them to operate at multiple wavelengths (multiple laser colors). In acne treatment, they are primarily used to treat scar tissue, hyper-pigmentation and to restore skin elasticity. Nd:Yag lasers are not generally used for treatment of active acne infections.
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Er:YAG Laser Resurfacing
Er:YAG lasers use Erbium YAG as the lasing medium and produce an infra-red laser. It is used primarily for the treatment of wrinkles, acne scars, laser peels and other photo-rejuvenation procedures. Some systems, such as FRAXEL, use a fractional application approach, which leaves minute untreated areas amidst the larger treated area, to facilitate faster healing. Er:YAG lasers are often used in resurfacing procedures, which are common treatments for uneven and pitted skin resulting from acne damage. Er:YAG lasers are generally preferred for more superficial resurfacing, while carbon dioxide lasers are the choice for invasive treatment.
Diode Laser (Smoothbeam, LightSheer)
The diode laser is a semiconductor laser. The laser beam is absorbed by melanin and it is popular for laser hair removal applications. Diode lasers are the laser system of choice for the treatment of active acne infection. Diode lasers, particularly those with wavelengths near 1450 nm, can be used to specifically target the psilosebaceous unit. Treatment can damage the sebaceous glands within targeted follicles and ultimately decrease sebum production at the treatment site.
Radio Frequency Laser (Aluma, Syneron Matrix RF, eLIGHT, eMAX, 3DEEP Fractional Skin Resurfacing)
Radio Frequency (RF) treatments use radio frequencies instead of light (both are electromagnetic radiation, they just have different wavelengths). In addition to acne and acne scar treatments, RF lasers are used in surgical applications to ablate tissue in sensitive locations like the throat and prostate.
Carbon Dioxide Laser(SmartSkin CO2, AcuPulse, UltraPulse, FRAXEL RE:PAIR, QuadraLASE fractional CO2)
Fractional C02 Laser Skin Resurfacing
Carbon dioxide lasers produce an infra red laser which is absorbed strongly by water molecules. Carbon dioxide lasers are powerful lasers that are often used for ablative skin resurfacing. For skin resurfacing applications a focused laser is used in a rapid-pulsed mode, in a process called laser-abrasion. Skin resurfacing is used for treating acne scars, chicken pox scars, fine lines, wrinkles, sun damage, rhinophyma, actinic chelitis. A weaker application using an unfocused laser is used to treat problems such as skin tags, dermatosis papulosa nigra, warts, syringomas, moles, seborrhoeic keratosis, milia, sebaceous hyperplasia. Carbon dioxide lasers are a powerful tool but they carry the risk of scarring and pigmentary disturbances if mis-used by inexperienced hands. Carbon dioxide lasers are usually used for treatment of acne scars, but are occasionally used to correct active acne by targeting the sebaceous unit.
Alexandrite Laser (GentleLASE 755, Accolade, Apogee)
Alexandrite lasers produce a beam of light in the far red wavelength of 755 nm. It is absorbed by melanin and tattoo pigments in the skin. Rapidly pulsed alexandrite lasers are used to remove tattoos, benign pigmented lesions and other hyper-pigmented marks. Long pulsed alexandrite lasers are commonly used for hair removal.
Argon Laser (Affirm)
Argon lasers produce a beam with two wavelengths of blue/green light, 488 nm and 514 nm. These wavelengths are absorbed by hemoglobin and melanin. Argon lasers are used to treat skin diseases such as, hemangiomas, fine veins, spider nevi and acne rosacea.
The First Lasers Used Rubies as the Lasing Medium
Ruby lasers produce a red beam with a wavelength near 695 nm. They are commonly available with a Q – switched mode, which provides additional wavelength options. In high energy rapid pulsed mode, ruby lasers are used to remove tattoos, brown pigmented disorders like actinic lentigenes, freckles, nevi and dilated blue veins.
KTP Laser (DioLite, Aura, VariLite)
KTP lasers produce a green beam with a wavelength near 530 nm. KTP lasers are used in a variety of surgical applications. In acne treatment, they are occasionally used at low power to treat active acne lesions. It is thought that the green light if absorbed by the porphyrins (as with blue light therapy) and the resulting release of free radicals is toxic to the bacteria. Research has shown that KTP lasers are moderately effective at improving inflammatory acne symptoms.
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