Laser is an acronym for “Light Amplification of Stimulated Emission of Radiation”. This means using an energy source to heat up particles called photons which are emitted at a certain wavelength. These are absorbed by certain tissue components (target) and cause selective destruction of that tissue.
There are many types of lasers, each emitting a different wavelength and hence used for different targets. For example, pigment-specific lasers are used for skin pigmentation disorders like tattoos, freckles, lentigines and other types of skin pigmentation.
Vascular-specific lasers are used to destroy blood vessels e.g. in certain blood vessel (vascular) birthmarks or spider veins, or in the treatment of red bumps and red flushing of rosacea.
Ablative lasers destroy superficial layers of the skin and are used for the treatment of scars, superficial skin growths containing oil glands or sweat glands, and viral warts.
Fractional ablative lasers shave laser beams in thin columns to destroy only a fraction of the skin at a time, leaving normal skin in between to act a ‘reservoir’ of healthy skin cells for faster healing compared to ablative lasers. This is useful for acne scars, wrinkles and rejuvenation.
Hair removal lasers are used to remove hair. Your doctor will advise you on whether laser treatment is suitable for your skin condition and which type of laser can be used.
It depends on the condition and the laser used. For example, one may require only one session for destruction (ablation) of skin growths, 1-3 sessions for freckles and sun spots (lentigenes), 3-5 sessions for acne scars, 4-8 sessions for hair removal, 4-10 sessions for removal of tattoos and 8-10 sessions for vascular birthmarks.
It also depends on many factors like the depth and the thickness of the skin lesion and the potential for recurrence of the condition.
The interval between treatments varies, depending on the laser and type of skin problem e.g. monthly for fractional laser, 2 months for hair removal and 1-3 months for tattoos/pigmentation (longer if post-inflammatory hyperpigmentation occurs). Sometimes, the initial treatments may be more frequent (e.g. ‘laser toning’ weekly or fortnightly), but may be required less frequently as the condition improves.
In Singapore, for safety reasons, only medical doctors with appropriate training, certification and licensing can perform laser treatments in the area they have received training in (e.g. eye specialists use lasers in LASIK treatment but dermatologists do not). Dermatologists and plastic surgeons have received training during their advanced specialty training to perform laser skin treatments, but other doctors require further training and certification before performing laser skin treatments.
Lasers are not used for removal of just any blemishes and marks. They are generally not indicated for inflammatory skin conditions (e.g. eczema, acne, fungal infections) and conditions which will resolve spontaneously with time (e.g. post-inflammatory pigmentation). They are also not first-line treatment for conditions which frequently recur despite laser (e.g. certain pigmentary disorders such as melasma and some pigmented birthmarks) and those which can be easily treated with other methods. In these cases, because of the potential for complications and the high cost, the doctor will advise other types of treatment first, failing which laser is then considered.
Lasers may not be suitable if you suffer from medical problems that would predispose you to poor skin healing (e.g. advanced cancer, immune system disease, uncontrolled diabetes), have active skin infection or disease over the area, or have a tendency to form thick scars (keloids). Certain drugs such as steroids and isotretinoin (for acne) can also impair wound healing. The doctor is the best person to advise you on your suitability for laser treatment.
Skin infection, skin colour changes like redness, darkening or lightening, scarring and acne may develop after laser treatment. Although darkening after laser is usually only temporary, spots of whitening associated with aggressive and repeated treatment may sometimes be permanent. Your doctor will advise you on the precautions to take to avoid these complications. It is important to adhere to the doctor’s instructions and to return for follow-up after the laser treatment as complications can set in later even after the skin has healed.
Fig 1: Post-laser hyperpigmentation seen in the shape of dots within squares
Fig 2: Persistent pits after fractional laser resurfacing
Fig 3: Confetti hypopigmentation after repeated laser treatment