Laser in dermatology

Note to our readers. This page is overdue for an update; there have been significant changes in To be technology since it was originally written.

Introduction

The first lasers used to treat skin conditions occurred more than 40 years ago. Argon and carbon dioxide (CO₂) lasers were commonly used to treat benign vascular birthmarks such as port wine stains and hemangiomas. Although these birthmarks could be effectively lightened, a side effect was the unacceptably high rate of scar training. In the past 20 years, advances in laser technology have revolutionized its use in treating many skin conditions and congenital defects, including vascular and pigmented injuries, and the removal of tattoos, scars and wrinkles. There is a spectrum of laser and light technologies available for skin rejuvenation and rejuvenation.

Properties of laser light

"Laser" is an acronym: light amplification by the sshy memission of radiation

Lasers are high intensity light sources with the following properties:

• Monochromatic: radiation is single wavelength
• Consistent: the light beam waves are in phase
• Collimated: light beams travel in parallel

Laser light can be precisely focused on small spots with very high energy.

Light is produced within an optical cavity that contains a medium, which can be a gas (for example, argon, krypton, carbon dioxide), liquid (for example, dye) or solid (eg ruby, neodymium: yttrium-aluminum-garnet, alexandrite). The process involves the excitation of the molecules of the laser medium, resulting in the release of a photon of light when it returns to a stable state. Each medium produces a specific wavelength of light, which can be within the visible spectrum (400 violet to 700nm red) or the infrared spectrum (over 700nm).

Vascular skin lesions contain oxygen hemoglobin, which strongly absorbs visible light at 418, 542 and 577 nm, while pigmented skin lesions contain melanin, which has a wide absorption range in the visible and infrared wave bands. Infrared lasers are widely destructive because they are absorbed by water in and between skin cells (they are made up of 70-90% of water).

The goal is to destroy the target cells and not harm the surrounding tissue. Short pulses reduce the amount heated by damaged cells, reducing thermal damage that could lead to scarring. Automatic scanners aim to reduce the possibility of overlapping treatment areas.

What types of lasers are there?

There are several types of lasers used in laser skin surgery. Older laser technologies, such as CO continuous wave (CW) lasers₂ and argon have been replaced by quasi-CW mode lasers and pulsed laser systems. Picosecond lasers have very short pulses.

The wavelength peaks of laser light, the pulse duration, and the way that target skin tissue absorbs this determine the clinical applications of laser types.

What skin conditions can be treated with lasers?

Vascular lesions

Lasers have been used successfully to treat a variety of vascular injuries, including superficial vascular malformations (port wine stains), facial telangiectasiashemangiomas pyogenic granulomasKaposi sarcoma and poikiloderma from Civatte. Lasers that have been used to treat these conditions include argon, APTD, KTP, krypton, copper vapor, copper bromide, pulsed dye lasers, and Nd: YAG. Argon (CW) causes a high degree of nonspecific thermal injury and scarring, and is now largely replaced by quasi-CW yellow light and pulsed laser therapies.

The pulsed dye laser is considered the laser of choice for most vascular injuries due to its higher clinical effectiveness and low risk profile. It has a large point size (5 to 10 mm) that allows large lesions to be treated quickly. Side effects include postoperative bruising (purple) that can last 1-2 weeks and transient pigmentary changes. CrustChanges in texture and scarring are rarely seen.

New V-beam features provide ultra-long pulse duration for targeted energy blood vessels over a longer period, resulting in more uniform blood vessel Damage that reduces purple seen with previous pulse dye lasers. The addition of dynamic cooling increases comfort during treatment, allowing higher fluences (energy) to be delivered safely and effectively, so fewer treatments are required.

Vascular malformations associated with smaller, more superficial blood vessels respond better to treatment than larger, deeper vessels (which occur more frequently in older people). Therefore, it is best to start treatment early. Fading in an 80% occurs after 8 to 10 treatments on average. Additional treatment may be necessary if the injury resort

Treatment with quasi-CW lasers also produces effective results, but may be associated with an increased incidence of scarring and changes in texture. The most common side effects include mild erythema, edemaand transitory crusts.

Non-laser intense pulsed light devices can also be used to treat vascular injuries.

Pigmented lesions and tattoos

High-energy, melanin-specific QS laser systems can successfully clear or eradicate a variety of pigmented lesions. Treatable pigmented lesions include freckles and birthmarks, including some congenital ones. melanocytic naevi, blue naevi, Ota / Ito naevi and Becker naevi. Short pulse laser systems effectively treat injuries by limiting their energy by melanosomeswhich are the little ones granules containing melanin inside the pigment cells. The results of laser treatment depend on the depth of the melanin and the color of the lesion and, to a certain extent, are unpredictable. Superficially located pigment is best treated with shorter wavelength lasers, while removal of the deeper pigment requires longer wavelength lasers that penetrate deeper tissue depths. Caution Needed With Color Skin Laser Therapy, As Permanent hypopigmentation and depigmentation it can happen. Successfully treated injuries may recur.

Before any laser treatment of pigmented lesions, any lesions with atypical features must be biopsied to rule out malignancy. The treatment of congenital melanocytic nevi is a controversial topic. The long-term effect of laser use on promotion melanoma It is not known, but the treatment is believed to be low risk.

QS laser systems can selectively destroy the tattoo pigment without causing much damage to the surrounding skin. The modified pigment is removed from the skin by removing white blood cells and tissues. macrophages. The choice of laser depends on the color, depth, and chemical nature of the tattoo ink. Two to ten treatments are often necessary. Yellow, orange and green are the most difficult colors. to remove.

• Black: QS ruby, alexandrite or Nd: YAG
• Blue and green: QS ruby, alexandrite
• Yellow, orange, red: QS Nd: YAG or PDL

As with other laser treatments, pigment and texture changes, including scarring, may occur.

Picosecond Nd: YAG and Alexandrite lasers have been found to eliminate exogenous pigment more effectively than QS lasers.

Hair elimination

Lasers can be used to remove excessively and aesthetically disabling hair due to hypertrichosis or hirsutism Laser treatments remove dark hair quickly, and it may take 3-6 months before regrowth is evident. Several treatment cycles are required with the space between treatments depending on the area of the body being treated. Laser treatments are less painful and much faster than electrolysis. Complications are rare, but superficial burns, pigmentary changes, and even scarring can occur. Increased growth of fine, dark hair has been reported in untreated areas close to the treated. Both increased and reduced located Sweating has been reported after treatment.

Suitable devices include ruby and alexandrite long-pulse lasers, a diode (810 nm), millisecond Nd: YAG, and intense pulsed light without laser.

Facial wrinkles, scars and sun damaged skin.

Laser facial rejuvenation uses high-energy, pulsed and scanned lasers.

Pulsed CO₂ and Erbium: YAG lasers have been successful in reducing and eliminating facial wrinkles, acne scars, and sun damaged skin. High energy CO, pulsed and scanned₂ The laser is generally considered the gold standard against which all other facial rejuvenation systems are compared. An improvement in 50% is usually found in patients receiving CO₂ laser treatment. Side effects of treatment include post-operative sensitivity, redness, swelling, and scarring. The redness and tenderness last for several weeks as new skin grows over the area where the damaged skin has been removed by laser treatments (ablative laser systems). Secondary skin infection Including reactivation of herpes is also a potential problem until healing occurs. Extreme caution is needed when treating dark-skinned individuals as a permanent or variable loss pigmentation It can occur in the long term.

Erbium: YAG produces similar results and side effects to CO₂ To be. Despite their side effect profile and long recovery time, these ablative laser systems, when used properly, can produce excellent results.

Non-ablative lasers have recently been used to dermal modeling; 'non-ablative' refers to heating of dermal skin collagen avoiding damaging the superficial cells of the skin (epidermis) cooling it. Multiple treatments are required to soften the skin.

Keloids and hypertrophic scars

Keloids and hypertrophic scars are difficult to eradicate, and traditional treatments are not always successful. Vaporizing lasers (CO₂ and erbium: YAG) have been useful as an alternative to conventional surgery. More recently, PDL has been used to improve hypertrophic scars and keloids. This may require multiple treatment sessions or the simultaneous use of intralesional injections for good results. PDL has been reported to reduce redness and improve scar texture and flexibility.

Other uses for laser in dermatology

Lasers are sometimes used to remove viral warts by vaporization (CO₂ laser) or destruction of dermal blood vessels (PDL), but evidence suggests that this is no more effective than standard wart paints or even waiting for spontaneous removal.

The co₂ The laser can be used to remove a variety of skin lesions, including seborrheic keratosis and skin cancers by vaporization or in cut mode. However, conventional surgery or electrosurgery can also be used and are generally less expensive.

Violet blue metallic halide light (407-420nm) has been used to treat acne because it has a toxic effect on acne bacteria, Cutibacterium acnes.

The Excimer laser uses noble gas and halogen to produce Ultraviolet radiation (308 nm) that will eliminate psoriasis plates. However, the small size of the stain and the tendency to blister make the treatment time consuming and difficult to perform.

Laser safety

Safety precautions will depend on which laser system is used and in what configuration. They must include:

• Thorough training of staff.
• Eye protection for the patient and clinic staff.
• Warning notice outside the procedure room
• Use of non-reflective instruments.
• Avoid flammable materials.

Adverse effects of the laser.

Laser treatments are burns. The following side effects may occur:

• Temporary pain, redness, bruising, blisters, and scabs
• Infection, including reactivation of herpes simplex
• Pigment changes (brown and white marks), which may be permanent.
• Scars