Photoaging is the main culprit for most benign pigmentation lesions such as ephelides (freckles), solar lentigines (sun spots). Mottled pigmentations are expressed as mixed hyper and hypopigmentation area. Other pigmentation conditions are not direct results of UV exposure. However, the sun exposure will undoubtedly exacerbate the problem and make it worse. Such conditions include mainly Melasma and poikiloderma of Civatte. In this post, we will not discuss the neoplastic lesions such as melanomas and pigmented basal cell carcinomas. Laser treatment is considered the standard gold treatment for benign pigmentation in general.
One of the most common benign pigmented lesions seen in the photoaged skin is Solar lentigines (sun spots). They are mainly found on the face, neck, chest and other sun-exposed areas of the body. Sun exposure will result in increased size and darken the color of these round bark brown. Freckles (Ephelides) are generally smaller and lighter, and the color changed seasonally. Melasma, on the other hands, differ in the shape and color. It presented itself as reticular patches and brown macules on the face, typically involving the cheeks, upper lip, forehead, and chin. Melasma is more complicated as it includes hormonal changes such as pregnancy and as a side effect of contraceptive.
All pigmentation lesions, regardless of the cause, are results of dysregulation (mainly overproduction) of melanin synthesis and abnormal deposition. Freckles and sunspots are mostly due to irregular melanin synthesis and deposition in the epidermis, while melasma and PIH are mixed of epidermis and dermis involvement.
The photothermolysis is the central principle of using the laser as a treatment for pigmentation lesions. The chromophore is either the melanin itself or the water in the surrounding tissues.
Melanin absorbs light between 600-1200 nm, preferably to the shorter wavelength.The central wavelengths used are KTP (532 nm), ruby (694 nm), alexandrite (755 nm) and Nd:YAG (1064 nm). Q-switched (QS) lasers generate very short pulse widths, in the nanosecond range, that fits well with the melanosomes characteristics (very small in size, approximately 1 μm, and full of the chromophore melanin). Another advantage of the nanosecond laser is to utilize photoacoustic vibration as well as selective photothermolysis for removal of pigmented lesions.
Another laser such as non-ablative fractional 1550 and 1927 nm (Fraxel dual) has Skin resurfacing properties as it uses water as the target chromophore, which significantly absorbs light above 1200 nm. These lasers are used primarily for collagen remodeling effects to treat wrinkles, scars, and skin tightening but can also be used to treat pigmented lesions. When skin is irradiated with a resurfacing laser, water in the dermis energy and is heated. The epidermal and dermal tissue is removed, and pigmented lesions are removed nonspecifically along with this tissue.
The best treatment for any pigmentation lesions is a combination protocol of Q-switch nano-second laser along with fractional resurfacing treatment. Usual the initial procedure is performed by Fraxel, followed by maintenance session using the q-switch nano-second laser (lutronic spectra). The patient has to be on skin lightening treatment using hydroquinone products for 6 weeks before the laser treatment and 4 weeks after to avoid the possibility of PIH. Hydroquinone has to be stopped for 1 week before any laser treatment. Restricted No-sun exposure or tanning for 3 months should be followed by Fraxel treatment.
Dr. Kamal Alhallak
Ph.D., MSc, CDE, CRE, APA, MBA candidate
Director of Albany Cosmetic and Laser Centre INC
Edmonton once had a municipal government (council-commission board) and each council rules for 3 years.