Lasers and Lights for the Skin -

Torunn Sivesind, M.D.

With the rapid evolution of medical technology, it can be difficult to weed through the many options available to the consumer for elective procedures. This holds true particularly for cosmetic dermatological procedures including laser and other light based treatments for common skin concerns like sun damage and premature skin aging.

The application of energy from light sources in order to improve the appearance and function of the skin first began several decades ago and has since become much more refined and popular. Laser and other light based treatments are able to meet the needs of a wide range of patients and can be tailored to the unique needs of each individual.

Conditions that can be treated with lasers and other light sources are numerous and include signs of premature skin aging, such as sun spots and mild to moderate wrinkles, broken capillaries (telangiectasias) and other vascular lesions, and skin surface irregularities and scars. There are many different types of lasers such as ablative, non-ablative, and fractional lasers. There are also specialized lasers to treat blood vessels ( vascular lasers), skin pigmentation, and excessive hair growth.

This article will focus primarily on the ablative and fractional lasers and intense pulse light ( IPL), which is a non-ablative, non-laser light source that can treat a variety of skin issues.

The interaction of lasers with skin tissue was first explored by Leon Goldman in the 1960s. The idea of applying lasers to cause “photothermolysis” (destruction of tissue by light and heat) by means of pulses of radiation was described by Anderson and Parrish in 1983. Since these pioneers paved the way, the carbon dioxide (CO₂, or “traditional”) laser gained wide popularity in the 1990s, enabling dramatic improvements in the skin.

The original CO₂ lasers were fully ablative, meaning they removed the entire epidermis ( upper layer of skin). Such lasers are still considered by many to be the standard by which other lasers are measured. Their ability to produce impressive results is unmatched, though they carry significant downsides — namely, potential side effects such as a lengthy period of redness and sometimes eventual hypopigmentation (loss of skin color). Recovery also mandates a significant period of “downtime.”

Another option in the ablative laser category is the erbium:yttrium aluminum garnet (erb:YAG) laser, which is similar to the CO₂ laser for its use as a resurfacing treatment to improve the appearance of wrinkles, scars, and acne. Available literature suggests that the efficacy of erbium:YAG is less than that of the CO₂ laser, yet it is associated with a milder side effect profile.

The erb:YAG laser is often used in younger patients with more superficial skin concerns, such as fine lines and wrinkles, while the CO₂ laser can be used for deeper wrinkles, scars, and even warts. CO₂ treatment modes can be adjusted in order to address a wide spectrum of concerns, from superficial issues like fine lines and textural irregularities to deeper lines and wrinkles, scars, and furrows. Both types of ablative laser have proven efficacy and are well-tolerated by most people.

Technological advances since the advent of the traditional CO₂ laser have facilitated a “happy medium” of sorts, whereby it is now possible to achieve many of the dramatic benefits seen with traditional ablative laser treatments while also reducing the limiting side effects of traditional laser resurfacing. In 2004, Manstein and others developed a resurfacing technique that utilizes a fractional pattern of thermolysis in which tiny columns (fractions) of skin are targeted, sparking the development of so-called “fractional” (or “Fraxel”) lasers in both ablative and non-ablative forms.

In the non-ablative realm, Intense Pulsed Light (IPL) is a treatment that leaves the epidermis intact while heating up the underlying dermis ( second layer of skin), stimulating collagen production and making the skin more taught. IPL delivers light of multiple wavelengths to target specific pigments in the skin, such as hemoglobin (red pigment) in blood vessels, and melanin (brown pigment) in sun spots and freckles. Filters enable customization of IPL to target unique concerns.

IPL has demonstrated efficacy in treating rosacea, telangiectasias, and sun spots. It can also be used for hair removal. Since multiple wavelengths are emitted by IPL, multiple color-containing molecular components (including melanin, hemoglobin, water, and collagen) can be targeted with the same treatment. Light destroys the excess pigments and also catalyses new cell growth. The controlled injury caused by the IPL wavelengths leads to stimulation of collagen production in the dermis as well.

The Science Behind Ablative Laser-Based Skin Treatments

Within the dermis, heat energy causes collagen fibers to denature and shorten by about two-thirds their original length. This contracture is responsible for the tightening of skin seen with laser treatments. Intracellular water vaporization is responsible to a lesser extent for this tightening effect. After heat injury, the skin’s regenerative healing response is triggered, with tissue enzymes working to break down the collagen remnants.

Creation of new collagen in the dermis is a long process, lasting several months. In fractional treatments, the epidermis is quickly rebuilt via epidermal cells located in regions adjacent to the areas of injury, while with fully ablative treatments, the epidermal regeneration occurs when new cells migrate from skin appendages such as hair follicles. The skin appendages are able to survive injuries to the epidermis such as those occurring with ablative resurfacing treatments, and are therefore fundamental to restoring a healthy epidermis

While different types of ablative lasers exist — which differ primarily in the wavelength of light they deliver — all ablative lasers are characterized by acting to remove all or part of the skin’s epidermal layer. Light energy is delivered to skin cells and is absorbed as energy in the form of heat. This heat energy is absorbed by water in the body’s tissues, heating up the cells until the water boils and the cells containing water evaporate (are ablated). Cells surrounding the area targeted by the laser absorb heat as well, resulting in coagulation of blood (hemostasis) and stimulation of fibroblasts to produce new collagen.

Ablative lasers do not target specific pigments in the skin (unlike IPL treatments) and the aim of ablative resurfacing is to cause controlled injury to the epidermis in order to stimulate a healing response. This ultimately leads to firmer, smoother skin when the ablated skin cells are replaced by the body’s regenerative response.

What to Expect with Ablative Laser Treatment

A single ablative treatment is often sufficient to achieve the desired results, though sometimes more than one session is needed depending on the severity of the skin condition being treated. A series of preparations is needed prior to the ablative laser therapy, in order to ready the skin for laser resurfacing. Sun exposure must be avoided prior to treatment, and all skin care products containing vitamin A derivatives, such as retinol, and hydroxy acids must be discontinued. Medications such as antivirals may also be prescribed to prevent outbreaks of herpes simplex (cold sores).

During the treatment, application of a topical anesthetic or other pain control is required. Post-treatment, dressings are applied to the skin, which will be raw and draining, as though severely sunburned. This can last for a week or two after the treatment. Follow up appointments are needed to check the healing process. Within two to four weeks, new skin will grow and cover the wounds — this new skin is often pink or red for weeks to months, but can be covered with makeup.

What to Expect with IPL Treatment

Treatment with IPL can require up to five sessions spaced two or more weeks apart, though some milder conditions may be treated in a one or two sessions. Maintenance treatments may be performed every six to 12 months, and a good skin care regimen with sun protection is essential to maintaining results.

Since IPL targets dark pigments in the skin, it is not always suitable for individuals with darker skin complexions. Side effects can include itching, redness, burns, scabs, scars, or discoloration. Pregnant women should not be treated, because the hormonal changes of pregnancy cause ongoing fluctuations in skin pigmentation. Avoidance of sun exposure is required prior to and after treatment, and skin care products containing vitamin A derivatives such as retinol should not be used for a week before and after treatment.

In Summary

With the abundance of laser-based treatment options available today, it is possible to achieve substantial improvement in a wide range of skin conditions. There is no single “best” treatment option. The ideal treatment type and regimen should be individualized to meet the unique needs and goals of each person. Any decision to pursue laser treatment should be made after a careful discussion of goals, expectations, and the potential risks and benefits. Ideally, this should occur in conjunction with a board certified physician or surgeon. Optimal results are achieved when patients are able to make decisions based on a basic knowledge of the available treatment options, the science behind those options, and when open discussion between patients and providers is encouraged.

References

Ramsdell, William M. “Fractional carbon dioxide laser resurfacing.” Seminars in plastic surgery vol. 26,3 (2012): 125-30. doi:10. 1055/s-0032-1329414

Lim, Hee Sun et al. “The efficacy of intense pulsed light for treating erythematotelangiectatic rosacea is related to severity and age.” Annals of dermatology vol. 26,4 (2014): 491-5. doi:10.5021/ad.2014.26.4.491

Patidar, MV et al. “The efficacy of intense pulsed light therapy in the treatment of facial acne vulgaris: comparison of two different fluences.” Indian journal of dermatology vol. 61,5 (2016): 545-9. doi: 10.4103/0019-5154.190115

Schoenwolf NL et al. “Intense pulsed light.” Current problems in dermatology vol. 42 (2011): 166-72. doi: 10.1159/000328446

Chen KH et al. “A systematic review of comparative studies of CO2 and erbium:YAG lasers in resurfacing facial rhytides (wrinkles). Journal of cosmetic and laser therapy vol. 19,4 (2017): 199-204. doi: 10.1080/14764172.2017.1288261

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