BOSTON – Patients with rosacea, particularly the erythrotelangiectatic form, are considered good candidates for treatment with lasers and light therapies, but for acne, treatments with these therapies are still in the development stage.
For acne, treatments that are being studied include those that target the sebaceous glands, according to Mathew M. Avram, MD, who spoke about laser and light therapies for acne and rosacea at the American Academy of Dermatology summer meeting.
Light therapies for rosacea
Oxyhemoglobin in the blood absorbs light from lasers at wavelengths of about 595 nm (pulsed dye laser) and 532 nm (KTP laser), creating heat that helps destroy capillaries that contribute to the appearance of rosacea. Over a period of 3-4 weeks, the vessels are resorbed, and facial redness diminishes.
Patients with rosacea that are expected to do best with laser therapy are those with telangiectasia. Laser therapy is also effective for background redness but will be less effective for people with the papules associated with rosacea and “almost not effective at all for preventing flushing,” Dr. Avram said in an interview at the meeting.
Intense pulsed light (IPL) is another modality for treating rosacea. As with lasers, the mode of action is heating of certain structures and chromophores, causing their destruction and resorption, but unlike lasers, IPL output is broad spectrum and can be modified using filters.
With IPL, “basically, the endpoint that you want to see is transient purpural change, just a fleeting period of some black and blue, or if you’re treating vessels, you want to see vessel clearance when you’re firing the laser or the intense pulsed light,” said Dr. Avram, director of the Massachusetts General Hospital Dermatology Laser & Cosmetic Center, Boston.
On-screen settings of laser or IPL devices are essential, “but ultimately, if you want to have an effective treatment you really have to see what’s happening to your target … you need to pay attention to clinical endpoints, which is seeing that black and blue or that vessel clearance, not just paying attention to what’s on the screen.”
With IPL, too much pressure can compress vessels and blanch the skin, resulting in a less effective treatment, he added. He noted that tissue graying, whitening, or contraction indicates overly aggressive treatment, with the risk of scarring.
Certain factors can reduce the efficacy of IPL treatments of rosacea. Dr. Avram recommended against treating tanned skin and pointed out that anemic patients may benefit less from this approach since less hemoglobin presents a less-absorptive target for the treatments. He also advised particular caution when treating darker skin phototypes. But the most common factor that may make these treatments less effective is when a patient is on any type of anticoagulant, including NSAIDs or warfarin (Coumadin), because the mechanism of action is immediate microvascular hemorrhage, thrombosis, and eventual resorption.
For best results, Dr. Avram advises “appropriate overlap with the laser” to get an even and uniform improvement in the redness, with about a 15% overlap. Spacing laser spots too far apart can result in “foot printing,” the appearance of clearance in the areas of the laser pulse, but not in areas immediately around it “so it looks almost polka dotted.” After treatments, all patients should avoid the sun, he added.
What’s ahead for acne treatment
Until now, laser and light-based treatments for acne, “have provided inconsistent benefits for patients and all too often disappointing results,” Dr. Avram said in the interview. But several developments on the horizon may offer more effective therapies based on completely different technologies than are currently available. “Each of these therapies will be targeting the sebaceous glands in order to provide improved treatment for acne.”
One is a cryolysis device that uses cooling to selectively target lipids in the sebaceous glands. (Cryolysis is similar to cryolipolysis, which uses cooling to target fat cells.) The lipid-filled adipocytes are more sensitive to cold than is the water-rich dermis, thereby preserving the surrounding structures. There are also laser wavelengths that are absorbed by lipids, one of which is at about 1720 nm. In this case, heating rather than cooling targets the lipids.
Another technology in development is the use of nanoparticles coated with elements such as gold that are massaged through the skin into the sebaceous glands. Laser treatment with multiple different wavelengths targets the nanoparticles, heating them within the sebaceous glands, resulting in improvements in acne. In this case, treatment does not depend on the absorption spectrum of lipids. Clinical trials of this approach are now underway.