Update on Melasma—Part I: Pathogenesis

Abstract

Melasma is a multifactorial dyschromia that results from exposure to external factors (such as solar radiation) and hormonal factors (such as sex hormones and pregnancy), as well as skin inflammation (such as contact dermatitis and esthetic procedures), in genetically predisposed individuals. Beyond hyperfunctional melanocytes, skin with melasma exhibits a series of structural and functional alterations in the epidermis, basement membrane, and upper dermis that interact to elicit and sustain a focal hypermelanogenic phenotype. Evolution in the knowledge of the genetic basis of melasma and the cutaneous response to solar radiation, as well as the roles of endocrine factors, antioxidant system, endothelium proliferation, fibroblast senescence, mast cell degranulation, autophagy deficits of the melanocyte, and the paracrine regulation of melanogenesis, will lead to the development of new treatments and preventive strategies. This review presents current knowledge on these aspects of the pathogenesis of melasma and discusses the effects of specific treatments and future research on these issues.

The mechanism of Croci stigma in the treatment of melasma based on network pharmacology and molecular docking

“…Melanocytes located in the basal layer of the skin are the site of melanin synthesis, especially melanosome, a lysosome‐related organelle in melanocytes 36 . When stimulated by stimuli like UV, melanocytes produce excessive concentrations of reactive oxygen radicals that not only damage cellular DNA but also undergo a complex series of reactions to trigger melanin production 2 . In this study, the following modalities were considered as possible mechanisms by which CS regulates melanogenesis (Figure 6).…”

“…As an acquired and intractable skin disease, melasma ordinarily occurs in the face of patients who frequently exposed to ultraviolet (UV) and short wavelength visible light (VL), and whose Fitzpatrick classification are IV ~ VI, of whom more than 90% are women 31 . The pathophysiological mechanism of melasma is complex, which is related to the activity and aggregation of melanocytes, inflammation, vascular proliferation and destruction of the basement membranes 2 . Among these, the activity of melanocytes and the aggregation of melanin in the true epidermis represent the most significant pathological features of melasma 32 …”

“…Melasma is a chronic localized melanotic pigmentation that is frequently seen on exposed areas in women 1 . It is universally acknowledged that melasma is a multifactorial disease that may result from the abnormal interaction of sun exposure, hormonal stimulation, altered oxidative status, and overlying skin in genetically predisposed individuals 2 . Because of the influence of many exogenous and endogenous factors, the pathogenesis of chloasma is complex and not completely clear so far.…”

New Mechanistic Insights of Melasma

“…A cross-sectional study on 400 pregnant women in Tehran showed the prevalence of melasma was 15.8%. 9 In a multicentric cross-sectional study from India, 15.2% of the subjects reported onset of melasma during pregnancy. 2 It has been reported that 8-34% of the women taking oral contraceptives or hormone replacement therapy develop melasma.…”

“…Positive family history of melasma was present in 54.7% of 400 pregnant women. 9 Family history of patients with Fitzpatrick skin type II and type III is not as pronounced as patients with darker skin (IV-VI). 10 When accounting for epidemiological risk factors, facial melasma seems most likely to display a dominant inheritance pattern, with exposure factors leading to disease development in genetically susceptible individuals.…”