Pulsed Dye Lasers (PDL)

Pulsed Dye Lasers (PDL) are occasionally used for the treatment of both active acne symptoms and acne scars. Although they can be used for multiple applications, Pulsed Dye Lasers are not usually not the first-choice of treatment for either active acne or acne scars.

On average, Pulsed Dye Laser treatment of acne and acne scars is reviewed as poor to moderate by patients after treatment. It is likely that PDLs are popular because they are a relatively inexpensive, versatile and common platform – but not because they are an effective for active acne or acne scars.

Pulsed Dye Lasers and Active Acne

There are a handful of clinical research studies that found Pulsed Dye Lasers may be effective for treating active acne infections. There are also a few studies that found PDLs were not effective treatments for active acne. This disagreement is likely because there are several different kinds of PDLs, and the treatments being researched are not all the same for every study.

Research studies on the use of PDL systems for the treatment of active acne for acne found that optimum results required at least four treatments. In addition, PDL-based treatment of active acne usually only provides temporary relief, and acne symptoms eventually return.

Pulsed Dye Lasers can be used as part of Photodynamic Therapy (PDT), which is a treatment that targets sebaceous glands and acne-causing P. acnes bacteria. Photodynamic Therapy works better with adjustable PDLs that are capable of producing a laser with a wavelength near 415 nm (ultraviolet), instead of the more common 595 nm (green/yellow). However, PDLs are rarely used for PDT because there are easier-to-use (and less expensive) light sources available for this treatment.

Pulsed Dye Lasers can also be used to directly kill acne-causing bacteria. The acne-causing Propionibacterium acnes bacterium produces a special molecule called porphyrin. When porphyrin is exposed to high intensity light at a wavelength around 420 nm (ultraviolet/blue) it generates free radical molecules which can kill the bacterium. This process is called Blue Light Phototherapy. Pulsed Dye Lasers are available that can generate high intensity light in this spectrum. However, other high-intensity sources of blue light (eg. LEDs) are substantially less expensive than PDL and are generally used for this type of acne treatment.

PDLs are also being studied as a way to selectively ablate the sebaceous gland, which then inhibits sebum production and reduces acne symptoms. While the research indicates using PDLs is a a viable approach, there are alternative lasers (eg. Diode Lasers) with longer wavelengths that are better suited for this application.

Pulsed Dye Lasers and Active Scars

The most popular dermatology application for Pulsed Dye Lasers is for the removal of birthmarks and other hyper-pigmented marks on the skin. Low-power Pulsed Dye lasers are also used to improve the appearance of wrinkles by stimulating regrowth of the tissue immediately underneath the skin.

Pulsed Dye Lasers can be used for two ablative and non-ablative treatments. Ablative treatments (ablative means to be removed or vaporized at very high temperature) utilize longer laser pulses and/or high light intensity to thermally damage or destroy the target tissue. Certain molecules, like oxyhemoglobin (found in red blood cells), preferentially absorb energy from Pulsed Dye Lasers. This feature makes Pulsed Dye Lasers a viable treatment for spider veins, erythematous acne scars and other skin discolorations caused by damaged or dilated blood vessels.

Both ablative and non-ablative PDL treatments are available for treating acne scars. Pulsed Dye Lasers are generally only used for the treatment of mild acne scars. Improvements in acne scars following PDL treatment are usually modest and superficial. The Pulsed Dye Laser platform is not well suited to correct severe acne scarring. This is because most PDL systems do not penetrate deeply enough into the skin tissue to correct significant acne scar damage.

How Do Pulsed Dye Lasers Work

Dye Lasers get their name from the fact that they use a specialized liquid dye suspension, instead of a crystal, as the source of the laser beam. Pulsed Dye Lasers (PDLs) are designed to deliver short bursts of light that last only a fraction of a second. Many Pulsed Dye Lasers can be adjusted (tuned) to create lasers of several different wavelengths (colors). For dermatology purposes, Pulsed Dye Lasers that produce laser beams at ~495 nm (green/yellow) are the most common.

Popular Pulsed dye laser (PDL) Systems

C-Beam, Cobra, Cynergy, Navigator, N-Lite, PhotoGenica, Regenlite, Vbeam.

References

Laser Treatment of Acne Vulgaris. Jih, et al. 2007.
Investigation of the Mechanism of Action of Nonablative Pulsed Dye Laser Therapy in Photorejuvenation and Inflammatory Acne Vulgaris. Seaton, et al. 2006.
Treatment of Acne Vulgaris With a Pulsed Dye Laser: A Randomized Controlled Trial. Orringer, et al. 2004.
Improvement of Facial Acne Scars by the 585 nm Flashlamp-Pumped Pulsed Dye Laser. Alster, et al. 1996.
Comparison of a 585-nm pulsed dye laser and a 1064-nm Nd:YAG laser for the treatment of acne scars: A randomized split-face clinical study. Lee, et al. 2008.