* Acceptable secondary publication
* This article was published in the Medical Lasers.
* The authors have received approval from the editors of the Medical Lasers and the D&PS.
Abstract
Melasma is a common acquired pigmentary disorder and difficult to treat with a high rate of recurrence. Conventional methods in the treatment of melasma have drawbacks and limitations. From a few years ago, the so-called “laser toning” treatment which uses a collimated low-fluence 1,064 nm Q-switched neodymium-doped yttrium aluminum garnet (QS Nd:YAG) laser has been introduced for the treatment of melasma. Laser toning has attracted much popularity and attention, and became a crucial treatment method of melasma. Although laser toning is now a mainstay for treating and managing melasma, there are excessive concerns about the risk of hypopigmentation in some dermatologists. The inordinate fear may have originated from a few studies which insisted that laser toning therapy have the high risk of hypopigmentation and should be considered a second-line treatment, not a first-line treatment for melasma. We share our clinical experiences and include a literature review regarding if hypopigmentation is truly an unavoidable and catastrophic complication of laser toning or not. It is thought that hypopigmentation is a preventable and controllable complication as much evidence suggests.
Key words: complication, hypopigmentation, laser toning, low fluence, melasma
Introduction
Melasma is a type of acquired hyperpigmentation that generally manifests in symmetrical brown patches over the face. The patches are light brown to dark brown in color and irregular in shape.1 Its etiology is yet to be fully understood and various causal factors and pathophysiologic processes are thought to be involved. Melasma tends to be more common in women of darker skin tones. In particular, East Asians including Koreans are prone to developing melasma and most eagerly seek treatment.2
Most cases of melasma are intractable and traditional treatment options include topical UV blocking agent, topical whitening agent, and peeling, etc.3 For quite some time now, lasers and intense pulsed light (IPL) have been used for the treatment of melasma. For removal of pigment, the Q-switched laser (alexandrite laser (755 nm), ruby laser (694 nm), or neodymium-doped yttrium aluminum garnet laser (532 nm)) and IPL were often used. However, these treatment modalities had a high risk of complications including hyperpigmentation or exacerbation of melasma.4 Such complications were thought to be associated with skin inflammation caused by excessive thermal damage with a high fluence.5
In more recent years, ‘a collimated low-fluence 1,064 nm Q-switched neodymium-doped yttrium aluminum garnet (QS Nd:YAG) laser’ with the top-hat beam mode, short pulse width, high peak power, and low fluence was used in the so-called “laser toning” treatment that minimizes thermal damage while clarifying the skin of melasma.6 Laser toning became a hot trend in East Asia and subsequently throughout the world. As many aesthetic clinicians have experienced and proven its effects and safety, laser toning has become an important treatment method of melasma.
Despite its popularity, laser toning is not without complications which have proven to be a source of a headache for many dermatologists. The most common complications include postinflammatory hyperpigmentation (PIH), hypopigmentation, rebound hyperpigmentation, and recurrence of melasma, etc. Among these, hypopigmentation may be the most dreaded complication of melasma treatment. (Hypopigmentation is also referred to as depigmentation, guttate hypopigmentation, mottled hypopigmentation, facial depigmentation, and punctate leukoderma, depending on the scholar. In this article, the word “hypopigmentation” will refer to all of the above conditions.)
This makes the outcome of laser toning disappointing and lower the patient satisfaction as well as cause permanent damage in some cases. Unlike other complications, some of the hypopigmented lesions are irreversible in spite of active treatment for repigmentation over a long time span.7-13 Concerns about the risk of hypopigmentation with laser toning is somewhat justified in that it can lead to better treatment outcome, however, excessive fear may not be helpful. Such an overblown fear may have stemmed from several reports such as A case series of facial depigmentation associated with low fluence Q-switched 1,064 nm Nd:YAG laser for skin rejuvenation and melasma which emphasized the risk of hypopigmentation with laser toning, questioning the appropriateness of using laser toning in the treatment of melasma.7-11
Various studies have pointed out that laser toning is associated with a high incidence of hypopigmentation. We would like to share our clinical experiences and include a literature review regarding whether hypopigmentation is truly a catastrophic and unavoidable complication of laser toning.
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To start the discussion on this topic, we first need to answer the question, “why does hypopigmentation occur during laser toning therapy?” Many dermatologists suspect that a high fluence and cumulative energy coupled with short treatment intervals and a large number of treatments, etc. to be the cause of this unwanted complication. However, there are very few studies in the literature that systematically examined the therapeutic outcome and incidence of complications associated with laser parameters. One can speculate about which causative factors of hypopigmentation associated with laser toning from literature review and examination of changes in treatment methods throughout time.
-To be continued
References
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