Pigmented lesions arise from a wide range of natural and environmental sources including photodamage, genetic makeup, and the ageing process. They may also manifest as side effects of medical procedures. Both can vary in size, shape, and prevalence in a given area. Pigmented lesions include pigment-related birthmarks, age spots, freckles, hyperpigmentation, actinic keratosis and pigmented nevi.
How Does It Work?
Treatment of pigmented lesions depends on the principle of selective photothermolysis; the proper wavelength is applied, and the light energy is absorbed by the chromophore and converted to heat which breaks up pigment. Surrounding tissue remains undamaged. In many cases numerous sessions are required to maximize results.
To successfully treat pigmented lesions one must carefully apply energy to break up pigment or blood but spare surrounding tissue. This can be more or less difficult depending on each patient’s individual characteristics such as skin colour. Practitioners can account for these characteristics by adjusting treatment parameters such as fluence, pulse width, and repetition rate to maximise delivery of energy (for better results) and minimise patient discomfort. Many devices are limited in their utility because the different parameters cannot be adjusted independently (if at all). Understandably, treatment of darker skin is more challenging due to the higher concentration of melanin in the skin as a competing chromophore; in those cases treatment may be too painful or cause burning.