Hair removal technologies expanding

September 1, 2005

Chicago — As the array of laser and light sources for hair removal continues to grow, so does their efficacy and safety, according to Vic Narurkar, M.D., a dermatologist in private practice and assistant clinical professor of dermatology at the University of California, Davis, School of Medicine (and president-elect of the American Society of Cosmetic Dermatology and Aesthetic Surgery).

"The premise has been that the mechanism for hair removal is follicular destruction, and the target is typically the melanin in the hair follicle. The challenge has been, how does one selectively destroy the hair follicle and preserve competing structures in the epidermis, specifically epidermal melanocytes at the dermal-epidermal junction?" Dr. Narurkar asks.

Over the years, he explains, "we've been able to maneuver these lasers and light sources to make them more effective to specifically target the follicle alone, thereby preserving the epidermis. The major advances in the last few years have involved ways to cool the skin. The best way to do that is to use continuous contact cooling and the appropriate wavelength of light and laser to target the follicle."

"These include the 694 nm (ruby), 755 nm (alexandrite), 800 nm (diode) and 1,064 nm (Nd:YAG)," Dr. Narurkar says.

A more recent advance has been the development of new-generation pulsed light sources that integrate contact cooling and more selective filters that can replicate some of the results only seen previously with single-wavelength lasers, he adds. An example is pulsed light that uses photon recycling and dichroic filters, which, Dr. Narurkar says, allows for pulsed light to replicate and even surpass results only achievable with single-wavelength lasers.

"The gold standard for light-based hair removal has been (equipment) operating in the 755 nm and 800 nm range. These wavelengths tend to target the greatest variety of skin types, with the lowest incidence of complications. With the development of very long pulse durations, the 800 nm laser particularly, is now able to treat all skin types, including the darkest skin types and tanned skin. The development of the new pulsed-light sources with contact sapphire cooling also are now able to address a greater variety of skin types with the greatest degree of epidermal protection," Dr. Narurkar says.

Complications

Complications arising from laser and light-based hair removal procedures typically stem from lack of appropriate cooling, he says.

"The greatest incidence of complications occurs with the long-pulsed 1,064 nm laser," Dr. Narurkar says. "That has to do with the fact that it has the least absorption of melanin. The idea was that this characteristic made it very safe to use in darker skin types. However, because of the higher fluences that are often necessary with this laser, the degree of epidermal compromise is the greatest. So when one uses this wavelength, one must be very careful to make sure one's technique is proper and that one uses adequate cooling."

Challenges

Challenges remain in achieving true long-term hair reduction in patients with very dark skin, he says.

"It has been my experience that in very dark skin, laser and light-source hair reduction has been more about maintenance," Dr. Narurkar says. "Typically, darker-skinned patients, particularly those with Type V and VI skin, require up to twice as many treatments as a comparable lighter-skinned patient."

He says the greatest promise for treating darker skin lies in the area of pseudofolliculitis barbae.

"Prior to the advent of lasers," Dr. Narurkar says, "treatments for this condition were relatively disappointing. However, we've had excellent results using both the long-pulsed 800 nm and 1,064 nm lasers for pseudofolliculitis barbae."

Going forward, photopneumatic technology, which the Food and Drug Administration just approved for hair removal applications this year, shows promise, according to Dr. Narurkar.