laser assisted hair removal for darker skin types
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Laser assisted hair removal for darker skin types

Before the advent of new safety procedures, laser hair removal had not been an option for people with darker skin. People with lighter skin types of I-III on the Fitzpatrick scale of skin color had been the only individuals that could safely benefit from laser treatment. Laser hair removal was often not an option for people with darker skin color as the lasers could damage pigmented skin. In laser hair removal, energy from the laser light is absorbed into pigmented cells. Those cells with more pibment absorb more energy. The energy damages the cells, usually through heat buildup which “cooks” the cells. This is good if you want to remove hair follicles, but bad if the skin around the hair follicles is also highly pigmented. Recently, however, there have been three advances in science which have made it possible for people with darker skin types to undergo laser treatment. Those advancements include the use of longer light wavelength lasers, the longer pulsed laser and more efficient skin cooling devices. With these advancements, patents with darker skin types IV-VI are now able to enjoy the benefits of laser assisted hair removal.

Scientists have recently improved the use of lasers by finding a way to focus the light beam on the hair shaft and bulb where the melanin is most rich and minimize the exposure of the surrounding skin to the laser energy. This is done by first determining the amount of time it takes for the hair shaft to achieve “thermal relaxation”. Thermal relaxation is a technical term that means “the time it takes for 50% of heat energy to be conducted away from a target tissue”. Once this thermal relaxation time is determined, scientists adjust the pulse duration of the laser to that same thermal relaxation time in the hair follicles. This time is usually found to be about 10 to 100 milliseconds in duration. The optimal laser pulse duration should be longer than the thermal relaxation time of the epidermis, allowing heat energy to be conducted away from the skin, but shorter than the thermal relaxation time of the hair follicle This confines the laser induced heating to the hair follicles structure. In other words, the heat induced by the laser builds up in the hair follicles because it cannot escape quickly enough, but it does not build up in the skin around the follicles as the heat can dissipate more quickly.

In order that the hair follicle be completely destroyed, the tissue immediately surrounding the hair follicle must also be diffused with heat. This surrounding tissue is the place where the stem cells for future hair follicles reside. The locations of stem cells exist in both the distal and proximal outer root sheaths of the hair follicle. These are located at the base of the hair follicle deep inside the skin. To reach these areas with the laser requires an even longer laser light pulse duration than is normally required. If the skin is darker, the melanin inhibits the light beam from reaching its eventual target at the base of the hair follicle. Instead, the light is converted into heat by the melanin and can cause a dangerous blister at the surface of the skin. With longer wavelengths, longer laser pulse durations and better cooling procedures, this problem can now be alleviated.

The cooling procedures on the skin have been improved in numerous ways. First, the longer pulse durations send the heat into the skin at a much slower pace. This allows the skin to naturally cool as the process is taking place. Inherent cooling devices such as direct contact of a cooling plate or cooled spray also added to the safety of the process.

There were two laser wavelengths that were found to be best for darker skin types. These were the diode (810 nm) wavelength and the Nd:YAG (1064 nm) wavelength. The diode wavelength was the shorter wavelength and also the most effective. The 1064 nm wavelength was longer but safer for darker skin types. In order to make the longer wavelength more effective for hair removal, shorter pulse durations could also be used with the Nd:YAG wavelength along with adjunct cooling methods in order to treat the darkest, and most sensitive Fitzpatrick skin type VI. The lasers, Nd:YAG and the diode, are both approved by the Food and Drug Administration and are now widely used in many clinics.

To determine the correct settings for the laser, the skin is evaluated at specific areas or "test spots" before starting the actual hair removal procedure. These spots are usually in the same area as where the treatment is going to take place. Of course, high profile parts of the skin, such as the face, have to be avoided in case there is an undesireable side effect. Also, the safest parameters, low fluence and longer pulse durations, are tested first in order to avoid any serious damage on the skin. The the settings on the laser a gradually increased until the desired effect is produced with minimal side effects. Special care is taken in areas with heavy amounts of hair because the heat often pools in those areas and can create damaging effects. After four tests and a 48 hour waiting period, technicians observe the skin for any serious damage.

In terms of the immediate test results and the determination of the correct fluence, laser technicians should look for several indicators. First, they would ask the patient if there had been any pain or discomfort. If there had been any pain, the fluence would be lowered. A topical anasthesia can also used if the patients experienced significant pain. Secondly, technicians would look to see if the treatment was even mildly successful in treating the unwanted hair. A mild response to the hair is known as "perifollicular erythema" and is a good indicator that the correct fluence has been obtained. Erythema involves a temporary reddening of the skin around the hair follicles in response to the thermal damage caused by the laser. A prolonged presence of perifollicular erythema would indicate that the fluence had been too high.

There had pareviously been certain medications and pre-existing conditions in the skin that had been considered unsafe to patients using laser treatment. These determinations, however, have been found to be mostly innacurate or unfounded. Photosensitizing drugs that had been activated by ultraviolet "A" wavelength light had been considered unsafe to some degree but the advent of newer lasers was now making this danger a thing of the past. Similarly, patients with a history of keloids or hypertrophic scarring were considered to be at higher risk of side effects from laser treatments. Newer lasers, however, also make this danger mostly irrelevant. Patients who had taken accutane were also considered to be at risk ofr side effects with laser hair removal, but the studies making claims about accutane are also unfounded. The only clear danger that scientists have determined involves patients who have experienced chronic or active herpes infections prior to their laser treatment. This is especially true if the infections existed in the proposed treatment area of the skin. To counter this danger, patients can be treated with antiviral drugsone day before the treatment and treatment continues for five to seven days after the laser treatment session.

Once laser treatment has been decided upon, there are certain preliminaries that must take place to prepare the skin. The patient’s skin must first be thoroughly cleaned and shaved. Any topical anesthetic that had been used should be removed and an alchohol cleansing should be performed at the location where the laser will be applied. The alchohol should be wiped away with water and the doctors and everyone present should put on protective goggles to avoid any damage to the eyes from the laser light.

Besides the already mentioned areas of the skin that have very dense hair, there are other areas that demand special attention so as to avoid any skin damage during laser treatment. The neck on female patients is especially prone to scarring and should therefore be treated with a lower laser fluence. The face is also a very sensitive area that should demand special care. It is especially crucial to thoroughly shave the upper lip prior to the treatment to avoid any damage to the skin.

It is considered to be very important that patients understand the laser treatment and its likely effects prior to receiving the treatment. There is usually some level of discomfort in the treatment that each patient should be informed about. Doctors should inform the patients that they will need multiple treatments to completely remove the unwanted hair. This is especially true for patients with darker skin types. Patients are also told not to use waxing or plucking of their hair follicles during the treatments. Shaving, however, and the use of depilatory creams is acceptable.

Laser treatment has become a great option for many special cases that were previously untreatable with conventional methods. Patients who used to experience folliculitis due to lasers and laser settings inappropriate for their skin type are now being treated with more refined and successful methods. Pseudofolliculitus is another condition which causes ingrown hairs around the beard and underarms which is now treatable with laser technology. Finally, Acne keloidalis nuchae, which plagues many African-Americans, is now successfully treatable with laser technology. Thanks to the newest discoveries in laser treatment, people with darker skin types will now enjoy all the benefits that those lighter skin types have enjoyed in the past from laser hair removal.

Laser assisted hair removal for darker skin types references

  • Battle EF Jr, Hobbs LM. Laser-assisted hair removal for darker skin types. Dermatol Ther. 2004 Jun;17(2):177-83. Review. PMID: 15113285
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