Melasma: A comprehensive update: Part I
TL;DR: A thorough understanding of the etiology of melasma and the research tools available to study this condition are crucial to enhancing management and developing novel targeted therapies of this often frustrating condition.
Abstract: Melasma is a common disorder of hyperpigmentation affecting millions of people worldwide. While it is thought to be triggered or exacerbated by sun exposure and hormones, much remains to be understood about its pathogenesis. A thorough understanding of the etiology of melasma and the research tools available to study this condition are crucial to enhancing management and developing novel targeted therapies of this often frustrating condition.
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01 Feb 2017
TL;DR: Prospective application of lignin peroxidase in skin-lightening functions through novel mechanisms holds high value for the cosmetics sector where it may serve as suitable alternative to hydroquinone; a potent skin‐lightening agent whose safety has generated lots of controversy and concern.
Abstract: Ligninolytic extracellular enzymes, including lignin peroxidase, are topical owing to their high redox potential and prospective industrial applications. The prospective applications of lignin peroxidase span through sectors such as biorefinery, textile, energy, bioremediation, cosmetology, and dermatology industries. The litany of potentials attributed to lignin peroxidase is occasioned by its versatility in the degradation of xenobiotics and compounds with both phenolic and non-phenolic constituents. Over the years, ligninolytic enzymes have been studied however; research on lignin peroxidase seems to have been lagging when compared to other ligninolytic enzymes which are extracellular in nature including laccase and manganese peroxidase. This assertion becomes more pronounced when the application of lignin peroxidase is put into perspective. Consequently, a succinct documentation of the contemporary functionalities of lignin peroxidase and, some prospective applications of futuristic relevance has been advanced in this review. Some articulated applications include delignification of feedstock for ethanol production, textile effluent treatment and dye decolourization, coal depolymerization, treatment of hyperpigmentation, and skin-lightening through melanin oxidation. Prospective application of lignin peroxidase in skin-lightening functions through novel mechanisms, hence, it holds high value for the cosmetics sector where it may serve as suitable alternative to hydroquinone; a potent skin-lightening agent whose safety has generated lots of controversy and concern.
199 citations
Cites background from "Melasma: A comprehensive update: Pa..."
...Hydroquinone and most of these alternatives operate through tyrosinase inhibition mechanism (Grimes, 2009), probably by binding directly to the enzyme or interacting with the copper molecules at its active site (Sheth & Pandya, 2011) thereby reducing the conversion of DOPA to melanin....
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TL;DR: The authors discuss the main clinical and epidemiological aspects of melasma, a chronic acquired hypermelanosis of the skin characterized by irregular brown macules symmetrically distributed on sun-exposed areas of the body, particularly on the face.
Abstract: Melasma is a chronic acquired hypermelanosis of the skin, characterized by irregular brown macules symmetrically distributed on sun-exposed areas of the body, particularly on the face. It is a common cause of demand for dermatological care that affects mainly women (especially during the menacme), and more pigmented phenotypes (Fitzpatrick skin types III-V). Due to its frequent facial involvement, the disease has an impact on the quality of life of patients. Its pathogeny is not yet completely understood, although there are some known triggering factors such as sun exposure, pregnancy, sexual hormones, inflammatory processes of the skin, use of cosmetics, steroids, and photosensitizing drugs. There is also a clear genetic predisposition, since over 40% of patients reported having relatives affected with the disease. In this manuscript, the authors discuss the main clinical and epidemiological aspects of melasma.
199 citations
TL;DR: A large number of patients with chronic hypermelanosis of sun‐exposed areas are diagnosed with atypical central giant cell granuloma, which is a leading cause of death in people with these patients.
Abstract: Background Melasma is a common acquired chronic hypermelanosis of sun-exposed areas which significantly impacts quality of life. There are few epidemiological studies in medical literature concerning these patients.
Objective Characterize clinical and epidemiological data on Brazilian female patients with melasma.
Methods A semi-structured questionnaire was administered to melasma patients treated at a dermatology clinic between 2005 and 2010. Association between variables was performed by multivariate regression models.
Results We assessed 302 patients; intermediate skin phototypes III (34.4%) and IV (38.4%) were prevalent. Mean disease onset age was 27.5 ± 7.8 years and familiar occurrence of melasma was identified in 56.3%. The most commonly reported trigger factors were pregnancy (36.4%), contraceptive pills (16.2%) and intense sun exposure (27.2%). Preferred facial topographies were zygomatic (83.8%), labial superior (51.3%) and frontal (49.7%). Pregnancy induced melasma has been associated to early disease (OR = 0.86) and number of pregnancies (OR = 1.39). Childbearing was correlated to melasma extension. Older disease onset age was associated to darker skin phototypes. Co-occurrence of facial topographies supported clinical classification as centrofacial and peripheral melasma.
Conclusion This population was characterized by: a high prevalence in adult females, intermediate skin phototypes, disease precipitation by hormonal stimulus and familiar genetic influence.
135 citations
TL;DR: It continues to be difficult to provide public health messages to guide safe exposure to the sun that are accurate, simple, and can be used by people with different skin types, in different locations, and for different times of the year or day.
Abstract: Due to the implementation of the Montreal Protocol, which has limited, and is now probably reversing, the depletion of the stratospheric ozone layer, only modest increases in solar UV-B radiation at the surface of the Earth have occurred. For many fair-skinned populations, changing behaviour with regard to exposure to the sun over the past half century - more time in the sun, less clothing cover (more skin exposed), and preference for a tan - has probably contributed more to greater levels of exposure to UV-B radiation than ozone depletion. Exposure to UV-B radiation has both adverse and beneficial effects on human health. This report focuses on an assessment of the evidence regarding these outcomes that has been published since our previous report in 2010. The skin and eyes are the organs exposed to solar UV radiation. Excessive solar irradiation causes skin cancer, including cutaneous malignant melanoma and the non-melanoma skin cancers, basal cell carcinoma and squamous cell carcinoma, and contributes to the development of other rare skin cancers such as Merkel cell carcinoma. Although the incidence of melanoma continues to increase in many countries, in some locations, primarily those with strong sun protection programmes, incidence has stabilised or decreased over the past 5 years, particularly in younger age-groups. However, the incidence of non-melanoma skin cancers is still increasing in most locations. Exposure of the skin to the sun also induces systemic immune suppression that may have adverse effects on health, such as through the reactivation of latent viral infections, but also beneficial effects through suppression of autoimmune reactivity. Solar UV-B radiation damages the eyes, causing cataracts and pterygium. UV-B irradiation of the skin is the main source of vitamin D in many geographic locations. Vitamin D plays a critical role in the maintenance of calcium homeostasis in the body; severe deficiency causes the bone diseases, rickets in children and osteomalacia in adults. Although many studies have implicated vitamin D deficiency in a wide range of diseases, such as cancer and cardiovascular disease, more recent evidence is less compelling, with meta-analyses of supplementation trials failing to show a beneficial effect on the health outcomes that have been tested. It continues to be difficult to provide public health messages to guide safe exposure to the sun that are accurate, simple, and can be used by people with different skin types, in different locations, and for different times of the year or day. There is increasing interest in relating sun protection messages to the UV Index. Current sun protection strategies are outlined and assessed. Climatic factors affect the amount of UV radiation received by the skin and eyes, separately from the effect of ozone depletion. For example, cloud cover can decrease or increase the intensity of UV radiation at Earth's surface and warmer temperatures and changes in precipitation patterns may alter the amount of time people spend outdoors and their choice of clothing. The combination of changes in climate and UV radiation may affect the number of pathogenic microorganisms in surface waters, and could have an impact on food security through effects on plant and aquatic systems. It remains difficult to quantify these effects and their possible importance for human health.
121 citations
TL;DR: Oral tranexamic acid may be an effective adjunct for refractory melasma and careful screening for personal and familial risk factors for thromboembolism should be done before initiation.
Abstract: Background Melasma is a common pigmentary disorder among Asians and treatment is challenging Oral tranexamic acid (TA) has emerged as a potential treatment for refractory melasma Large-scale studies on its use, outcomes, and safety are limited Objective We sought to evaluate treatment outcomes and adverse effects of oral TA in melasma in an Asian population Methods We conducted a retrospective analysis of patients who received oral TA for melasma in a tertiary dermatologic center from January 2010 to June 2014 Results In all, 561 patients (914% female, 86% male) were enrolled Median duration of treatment was 4 months The majority (503 [897%]) improved, 56 (100%) had no improvement, and 2 (04%) worsened Patients without family history of melasma had better response rates than those with family history (906% vs 600%, P = 01) Of the 503 who improved, response was seen within 2 months of TA initiation, with a relapse rate of 272% Adverse events occurred in 40 (71%) Most were transient, but 1 developed deep vein thrombosis requiring prompt discontinuation She was later given the diagnosis of familial protein S deficiency Limitations This was a retrospective study Conclusion Oral TA may be an effective adjunct for refractory melasma Careful screening for personal and familial risk factors for thromboembolism should be done before initiation
116 citations
References
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TL;DR: This article overviews the various inhibitors obtained from natural and synthetic sources with their industrial importance, and examines the role of tyrosinase in melanin biosynthesis and its role in dermatological disorders.
Abstract: Tyrosinase is known to be a key enzyme in melanin biosynthesis, involved in determining the color of mammalian skin and hair. Various dermatological disorders, such as melasma, age spots and sites of actinic damage, arise from the accumulation of an excessive level of epidermal pigmentation. In addition, unfavorable enzymatic browning of plant-derived foods by tyrosinase causes a decrease in nutritional quality and economic loss of food products. The inadequacy of current conventional techniques to prevent tyrosinase action encourages us to seek new potent tyrosinase inhibitors. This article overviews the various inhibitors obtained from natural and synthetic sources with their industrial importance.
913 citations
TL;DR: This review describes the different approaches to obtain depigmentation, suggests a classification of whitening molecules on the basis of the mechanism by which they interfere with melanogenesis, and confirms the necessity to apply standardized protocols to evaluate depigmenting treatments.
Abstract: Many modalities of treatment for acquired skin hyperpigmentation are available including chemical agents or physical therapies, but none are completely satisfactory. Depigmenting compounds should act selectively on hyperactivated melanocytes, without short- or long-term side-effects, and induce a permanent removal of undesired pigment. Since 1961 hydroquinone, a tyrosinase inhibitor, has been introduced and its therapeutic efficacy demonstrated, and other whitening agents specifically acting on tyrosinase by different mechanisms have been proposed. Compounds with depigmenting activity are now numerous and the classification of molecules, based on their mechanism of action, has become difficult. Systematic studies to assess both the efficacy and the safety of such molecules are necessary. Moreover, the evidence that bleaching compounds are fairly ineffective on dermal accumulation of melanin has prompted investigations on the effectiveness of physical therapies, such as lasers. This review which describes the different approaches to obtain depigmentation, suggests a classification of whitening molecules on the basis of the mechanism by which they interfere with melanogenesis, and confirms the necessity to apply standardized protocols to evaluate depigmenting treatments.
734 citations
TL;DR: In the hierarchy of therapies for melasma, the treating physician must consider the devastating psychosocial impact of pigmentary imperfections within the realm of the benefits and risks associated with each treatment.
Abstract: Background: Melasma is a common acquired symmetric hypermelanosis characterized by irregular light- to gray-brown macules and patches involving sunexposed areas of skin. Etiologic factors in the pathogenesis of melasma include genetic influences, exposure to UV radiation, pregnancy, hormonal therapies, cosmetics, phototoxic drugs, and antiseizure medications. Observations: Melasma is often a therapeutically challenging disease, and current treatments include hypopigmenting agents, chemical peels, and lasers. Hypopigmenting agents include phenolic and nonphenolic derivatives. Phenolic agents include hydroquinone and hydroquinone combination preparations. Despite controversies regarding the issue of hydroquinone-induced ochronosis, hydroquinone remains the most effective topically applied bleaching agent approved by the Food and Drug Administration for the treatment of melasma. Nonphenolic bleaching agents include tretinoin and azelaic acid. Superficial, medium, and deep chemical peels are more often used in lighter-complexioned patients. Such peels should be used with caution in blacks. Although lasers have demonstrated significant efficacy in the treatment of a variety of hyperpigmentary disorders, their precise efficacy and place in the therapy of melasma have yet to be established. Conclusions: In the hierarchy of therapies for melasma, the treating physician must consider the devastating psychosocial impact of pigmentary imperfections within the realm of the benefits and risks associated with each treatment. (Arch Dermatol. 1995;131:1453-1457)
440 citations