[Hinews] [Physician's Column] By Ara Bong, Director of Reset Clinic

The cornerstone of treating pigmentation disorders lies in a precise understanding of melanocytes. Melanin, primarily distributed at the epidermal-dermal junction, resides within melanosomes—tiny structures approximately 0.5μm in size with a thermal relaxation time (TRT) of about 250 nanoseconds. To effectively target these minute structures without damaging surrounding tissue, laser pulse durations must be shorter than the TRT, meaning below 250 nanoseconds.

A leading tool in this domain is the Q-switched laser, which delivers high-energy pulses in nanoseconds, optimized for selective photothermolysis. This technology generates photoacoustic shock waves within melanocytes, effectively breaking down pigment. It has long been a mainstay in East Asia for treating conditions like melasma and Ota’s nevus.

Melasma is classified into epidermal and dermal types based on lesion depth, each requiring tailored energy levels and treatment approaches. For instance, the Q-switched Nd:YAG laser, when used at a low fluence of 4 J/cm² or less, is ideal for subcellular melanosome targeting. Deeper dermal melasma, however, demands higher fluences above 4 J/cm² for cellular-level treatment. Pre- and post-treatment care, including melanin suppression and extracellular matrix (ECM) optimization, is critical for success.
Beyond laser parameters, clinical outcomes hinge on identifying the correct endpoint. The most reliable indicator is “delayed perilesional erythema,” where redness around the lesion appears after a time lag, signaling an effective response. If the effect is insufficient, practitioners may aim for “immediate perilesional erythema” by adjusting treatment intensity.

Ara Bong, MD, Director of Reset Clinic
Ara Bong, MD, Director of Reset Clinic


Emerging strategies like “dual-toning” combine Q-switched lasers with long-pulsed Nd:YAG lasers, targeting both epidermal pigment and dermal collagen and elastic fibers to reduce recurrence rates.

Additionally, treatments like needle radiofrequency (RF) targeting senescent fibroblasts and skin boosters have shown promise in improving melasma outcomes.
The advent of picosecond lasers, with even shorter pulse durations, has opened new possibilities. These devices excel in tattoo removal and treating clustered melanocytes, offering hope for recalcitrant pigmentation disorders unresponsive to traditional Q-switched lasers. Ultimately, the success of pigmentation treatment depends on a “precision design” tailored to the lesion’s characteristics and the patient’s skin condition.

In summary, effective pigmentation treatment requires a deep understanding of melanocyte biology, precise laser technologies like Q-switched and picosecond lasers, and customized approaches to optimize outcomes and minimize recurrence.

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