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Laser treatments for the skin, in a nutshell
LASER treatments for dermatological problems have become increasingly popular over the past few years. The increasing availability of machines and development of technology, coupled with increasing awareness of laser treatments has contributed to the growth of this segment of the aesthetic market.
Lasers for medical use work by the principle of Selective Photothermolysis. Different substances in the body preferentially absorb light energy at various wavelengths, producing heat energy and consequently changes to the organ or the body part that is being targeted. These substances that absorb the light energy are called chromophores. An example of a common chromophore for medical lasers is haemoglobin, present in our red blood cells. Haemoglobin absorbs light strongly at 400, 541 and 577nm. Therefore lasers targeting blood vessels usually produce light energy at these wavelengths. Other chromophores in the body include water and melanin, which is the pigment produced by the skin.
Laser treatments have now become the mainstay of treatment of a variety of skin problems such as pigmentation, acne scars and tattoo removal. Classified into broad categories, here are some common types of laser you might encounter at aesthetic/dermatologist clinics:
- Pigment lasers are usually non ablative lasers, which emit light energy that is selectively absorbed by pigments, resulting in break up of pigments. Depending on the type of pigment and the depth of pigment, different wavelengths of laser may be used. In general, a longer wavelength laser penetrates more deeply into the skin, but these may not be as effective for more superficial pigments. Pigment lasers are also used for tattoo removal. There are many brands of laser machines in the market for pigmentation. Just like cars, every brand of machine has its own strengths and weaknesses, but they all perform a similar function, and different clinics will offer different lasers depending on what is available and the doctor's familiarity with the particular machine.
- Rejuvenation lasers are usually longer pulsed lasers compared to pigment lasers. These work by producing heating in the dermis of the skin, stimulating collagen production, and some mild tightening effects.
- Fractional lasers are designed to resurface the skin. The treatment often produces some downtime in the form of redness and mild peeling and scabbing, but the downtime is less than with traditional ablative lasers. Some examples of fractional lasers include Fotona, Fraxel and Dermablate.
- Ablative lasers have the ability to cut into tissue. These are more commonly used by surgeons in an operating theatre setting, but dermatologists and aesthetic practitioners use them for procedures such as mole removal and milia. Ablative lasers for skin resurfacing causes significant downtime and therefore is getting less popular.
As with every medical procedure, there are potential complications that one should know about before undergoing laser treatments.
Acute skin reactions such as redness and itching are not uncommon after a laser procedure. This often occurs as a result of the skin reaction to the heat of the laser. Although this is quite common it is not a serious side effect and usually resolves by itself after a few days.
Burns and blistering happen infrequently and generally heal well if the wound is kept clean. Infections can occur with the more ablative lasers. These can be bacterial in nature or a reactivation of previous herpes virus infection.
Asian skin and skin of colour are often more tricky to treat than lighter or Caucasian skin. This is because of the risk of a condition called Post Inflammatory Hyperpigmentation (PIH). This occurs as a result of stimulation of pigment cells by the heat of the laser or inflammation. A study1 published in the British Journal of Dermatology in 2012 showed up to 92 per cent of patients developing PIH after ablative skin resurfacing and up to 13 per cent in patients undergoing non-ablative skin resurfacing.
Closer to home, studies done by the National Skin Centre in 2002 and a more recent one this year by Taiwanese doctors showed an incidence of PIH of about 33 per cent even with non-ablative lasers. This underlines the challenge faced by doctors in performing laser treatments in Asian skin. Fortunately, PIH usually resolves spontaneously after four to six months even without further intervention.
Hypopigmentation, which is the development of lighter patches of skin, can also occur after laser procedures and is more common and severe in patients with darker skin.
In my practice I often find myself having to address some common questions and misconceptions about laser treatments for the skin. Here are some of them.
1. My beautician can do laser treatment for me
In Singapore, skin laser treatments have to be done by certified doctors. These doctors need to have attended courses to certify them competent and knowledgeable in lasers, as well as have NEA approval and licences to purchase and operate medical grade lasers. The lasers and lights at beauticians are usually not medical grade lasers, and are more similar to the lasers used in laser pointers.
2. The stronger the laser the better.
The redder my face, the better.
This is a common misconception amongst patients who are looking for quick results and more value for money in their treatments. Lasers work by selectively targeting chromophores in the skin, producing heat energy in the process. If too much heating is achieved during the treatment, the skin becomes too stimulated and inflamed. This can lead to deposition of pigments by the pigment cells in the skin, resulting in Post Inflammatory Hyperpigmentation. Also, if a pigment laser is overdone on Asian skin, the chances of developing hypopigmentation or white spots on the skin increases exponentially.
Doctors usually treat patients to what we call a dermatological endpoint, meaning they are looking for specific skin reactions which indicate that the treatment is adequate. For example, for ephelides or freckles we would fire the laser at the spot until it turns grey, for skin rejuvenation we would run the laser on the skin until the skin turns slightly pink. It is also important to allow the skin to have adequate time for recovery and repair after each laser treatment, and most practitioners would recommend an interval of about a month between treatments.
Complications are much more likely to occur if performed past the desired endpoint and we would not advise patients to pressure their doctors to do so.
3. My friend had a laser done and one treatment was enough for her to see results, why is mine different?
Some pigments that are more superficial, like freckles and solar lentigines, can be treated with a laser that produces scabbing and peeling off of the pigments. This is not the case for deeper pigments like melasma and Hori's nevus.
Pigmentary problems are also usually multifactorial. Lifestyle, environmental and even genetic factors play a role in the severity of pigments and response to treatment.
4. Do I need to apply sunscreen and avoid the sun while I am doing laser treatment?
Sunscreen should be applied even if you are not doing laser treatment. As for sun exposure, the key is moderation. The human body requires some sun exposure to produce Vitamin D, so the keyword is moderation. However, it is important that we do not get exposed to the sun to the point of getting red, as this increases the risk of Post Inflammatory Hyperpigmentation after a laser treatment.
5. Lasers will thin my skin
This is untrue. Most lasers nowadays are non ablative lasers used for pigments and rejuvenation. These lasers do not have cutting properties and do not burn off any skin layers. For the fractional resurfacing lasers, theses actually stimulate collagen and new skin growth, so in fact, your skin will feel firmer after doing the treatments.
This series is produced on alternate Saturdays in collaboration with Singapore Medical Specialists Centre.