Hair removal

Vancouver, British Columbia - Side effects such as permanent discoloration can occur with the use of lasers for hair removal, so physicians should ensure they are using the proper light source and intensity when performing such procedures, says a presenter here.

Speaking at the 57^th Annual Meeting of the Pacific Dermatology Association, Dr. Iltefat Hamzavi, senior staff physician at Henry Ford Hospital in Detroit, discussed the uses of phototherapy, lasers and photodynamic therapy (PDT) in dermatology.

Challenges, side effects

Two major side effects that can occur with laser therapy are dyspigmentation or failing to achieve the desired outcome, Dr. Hamzavi notes.

"The most feared side effect is dyspigmentation," he tells Dermatology Times. "That can occur if the wrong laser is used or is at the wrong setting. I see up to one person a month who has severe dyspigmentation after laser hair removal. The other side effect is that the procedure doesn't work, but that is less serious than permanent discoloration.

"A longer wavelength, for instance, doesn't work as well on a fair-skinned person. The skin doesn't absorb enough light to destroy the hair follicle. More treatments are typically needed in fair-skinned people when using longer wavelength lasers."

The spot size of the light source is a factor that a clinician needs to consider when using laser therapy for hair removal, Dr. Hamzavi adds.

"If you are going to use the laser on an area like the back or the legs, you can do this much faster if there is a larger spot size," he explains. "It also allows you to reach deeper structures. If the use of the laser is limited to the face, then spot size would not matter that much."

Significance of cooling

There have been advances in cooling of lasers, Dr. Hamzavi notes. The significance of cooling when conducting hair removal is the ability of the laser to reduce the heat on the skin, which, in turn, reduces the risk of dyspigmentation.

Topical agents, such as eflornithine, which is believed to work by blocking an enzyme necessary for hair growth, can be complementary to using lasers for hair removal, Dr. Hamzavi explains. Used in between laser treatments, the topical cream will accelerate the reduction in hair growth. Data from the University of British Columbia showed eflornithine in combination with laser hair removal slowed down facial hair growth after 24 weeks of treatment with significant differences seen, compared to controls who applied a placebo cream, after eight weeks. The hair reduction was also more rapid on the eflornithine-treated side.

One of the uses of the carbon dioxide laser is assisting in the removal of tattoos, Dr. Hamzavi says. The Q-switched laser is typically used to remove tattoos. The laser pulses light onto the tattoo to break up the tattoo pigment. However, the process demands a lot of time, and doesn't completely remove the tattoo in many instances. When the CO₂ laser is used as an adjunct to remove remaining tattoo pigment it can enhance the results of laser tattoo removal. However, there is an increased likelihood of scarring.

Variety of skin conditions

Information was also presented on the use of targeted phototherapy to treat a variety of skin conditions.

A physician's decision to choose one light source over another would depend on the target, according to Dr. Hamzavi, noting some lasers are better suited to treating psoriasis while others are better suited to treating vitiligo. This is based on the fundamental premise that diseased skin has a different sensitivity to UV light. For example, in psoriasis the diseased skin can tolerate a much greater amount of UV light than the normal skin. Targeted phototherapy allows a physician to more selectively treat diseased skin. These devices can be lasers or broadband light sources that generally fall in or close to the optimal narrowband spectrum of UVB light for psoriasis.