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Everybody knows that melanin is the pigment responsible for suntans. The amount of skin melanin depends on the skin type and on ethnic characteristics. Moreover, melanin is known to absorb part of the energy emitted by the laser. This is why a phototype must be defined by the physician for each patient, according to the standard Fitzpatrick classification. The physician may also proceed to some tests in order to make the optimal adjustments on laser parameters.
1. The laser cannot destroy white hair
And it cannot destroy very light thin hair coats neither, as they contain very few or no melanin at all. But fortunately, this type of patient generally does not suffer from hair problems; and yet, could still undergo permanent hair removal using electrolysis.
2. Being careful not to stimulate the downy hair
The downy hair, or very fine hair, cannot accumulate much heat when "flashed" because of its small diameter. It will store enough heat to eliminate the stem and the bulb, but germinal cells will not be damaged.
But after such an attack, the downy hair might be stimulated and turn into terminal hair.
Areas covered with downy hair should thus be treated carefully. Areas presenting with terminal hair only, such as the underarms, the legs, and the bikini, do not present any risk of stimulation.
3. Blonds can now be perfectly treated
With the laser if the practitioner is qualified and well equipped! The main problem is that poorly pigmented hair do not develop much heat. Thus, more sessions will be necessary to obtain the same results as in a brown-haired woman. However, blonds can undergo a dynamic treatment as soon as the first session due to their light complexion.
4. Dark and black skins are treated with the Yag laser
The new Yag lasers finally convinced us. Indeed, it would be a euphemism to call us prudent when manufacturers launch new devices. However, we tested the laser on many black skins, and obtained close to permanent hair removal, a result comparable to that obtained with the Alexandrite laser. This marks a big advance in the treatment of high phototypes. Henceforth, in the worst case, a maintenance session is necessary approximately once a year.
This underarm has been treated on a small area (the light area). The picture on the right, presenting a patient with a very high phototype, shows that the treatment respects the skin. Indeed, there are no burns, and the presence of many papules guarantees the efficiency of the treatment.
5. Suntans are laser hair removal's worst enemy
As they can cause skin burns. It is now clear for everybody that before reaching the lowest parts of the hair, light energy must first penetrate the skin. If skin pigmentation is important, the skin might heat up and burn, and the amount of energy delivered by the laser to the hair bulb will be reduced. Sun and permanent hair removal are not compatible!
6. Light skins with dark hair
Are perfect for this type of treatment. Moreover, patients with such characteristics suffer a lot from aesthetic problems linked to their hair.
Protecting the skin from the heat
Laser light is absorbed by the melanin present in the hair, which is shaved before the treatment in order not to waste the energy and not to heat the skin pointlessly.
By luck, the hair store the heat, while the skin cools down very fast. This interesting property is used to heat up the bulb without damaging the skin.
Once heated, the hair frees the heat energy it has stored. This energy spreads throughout the hair and destroys its lower structures, the bulge and the germinal matrix, where new hair are synthesized.
The outer layer of the skin (epidermis) is the laser's weak point: hair have to been burnt in depth, but without damaging the skin surface.
This is why a third rule of laser hair removal exists: be sure the laser is equipped with an efficient skin cooling system. Side-effects (superficial burns and pigmentation disorders) only occur if the skin is affected.
The goal is to keep the skin temperature low by cooling it down actively. The first cooling systems consisted in ice or gel applied directly on the skin. Then, more elaborated techniques appeared such as the projection of cryogenic spray, or cold air blown constantly.
Skin cooling devices are both known to be space wasting and efficient. These devices have become nearly as big as the laser devices themselves along with the advances in technologies. But they insure both tolerance and efficiency. They also numb the skin by lowering the skin temperature.
The CrioJet blows a constant air flow at a -60°C temperature. It provides skin cooling before, during and after the shot, as well as comfort for the patient.
There exist several types of skin complications related to laser. The most obvious being burns, which are always very superficial. But pigmentation disorders may also occur, such as hypopigmentation if cells synthesizing melanin (the melanocyts) are destroyed, or, more frequently, hyperpigmentation, that is the development of dark marks. With decent material, these accidents almost never happen on light skins.
On darker skins, laser acts like prolonged exposure to the sun and can induce variations in skin pigmentation. These marks generally disappear rapidly, but it can sometimes take a few months before the skin gets totally clear!
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