Melasma In Men
Introduction
Melasma, also known as chloasma or the mask of pregnancy, is a common acquired pigmentary disorder that manifests in affected individuals as confined, symmetrical, hyperpigmented macules primarily on sun-exposed areas, particularly the forehead, cheeks, upper lip, nose, and chin. Although it affects all skin types, darker individuals tend to have more severe and recalcitrant melasma. Melasma is reported to affect as many as 5 million people just in the United States and severely impacts patients' self-reported quality of life as measured by validated quality-of-life indices.
Prevalence rates for melasma vary from 8.8% in certain populations in the Southern United States to as high as 40% in some Southeast Asian populations. However, the true incidence and prevalence rates are difficult to determine, as few studies have pursued random sampling of the general population.
Virtually all demographic studies have sampled predominantly female patients, reflecting the fact that melasma is generally considered a disease of this gender. Men make up a comparative minority of those afflicted with melasma as reported and confirmed in multiple studies across different populations (Table 1). As a result of this discrepancy, investigative work in determining the unique characteristics of melasma in men has lagged behind similar studies in female patients. However the prevalence of melasma is higher in studies conducted in India compared to similar work in other countries, a finding that is only partially explained by the prevalence of darker skin tones in Indian populations.
Table 1. Prevalence of melasmain men worldwide
| Author | Location | No. of patients sampled | Percent of cases of melasma in men |
| Vasquez et al. | South America | Not reported | 10% |
| Hexsel et al. | Brazil | 953 | 3% |
| Sarkar, Jain et al. | India | 120 | 26% |
| Sarkar, Puri et al. | India | 200 | 21% |
| Achar et al. | India | 312 | 20% |
| Jang et al. | South Korea | Not reported | 4% |
| Goh et al. | Singapore | 205 | 5% |
| Guinot et al. | Tunisia | 197 | 5% |
The major suspected etiology behind the discrepancy in prevalence rates is chronic outdoor sun exposure. Many patients report outdoor occupations (58.5%) or frequent sunlight exposure (48.8%), and a study in Latino males noted greatly elevated rates of melasma (36%) in one group of outdoor migrant workers. Another possible contributory factor is the application of mustard oil, a cutaneous photosensitizer, for body and hair massage, a cosmetic nuance unique to Indian culture. Although its photosensitization properties suggest a possible role for mustard oil in the development of melasma, it has not been investigated in great depth in other studies. Furthermore, reports of similarly high levels of melasma prevalence in other study populations with frequent sun exposure diminish the role mustard oil might play in comparison to other risk factors such as ultraviolet radiation exposure.
Pathogenesis
The mechanism of lesion pathogenesis in melasma is incompletely understood at present. Current hypotheses include activation of fibroblasts and up-regulation of stem cell factor and c-kit secondary to dermal inflammation from ultraviolet radiation leading to increased melanogenesis, as well as a possible vascular component based on findings of increased vascularity in melasma lesions. Alternatively, UVB exposure promotes keratinocyte production of interleukin 1, endothelin 1, alpha-melanocyte stimulating hormone, and adrenocorticotropic hormone - all signaling molecules that may stimulate melanogenesis. Although the precise cause is unknown, prior investigation in women has identified strong associations between melasma and certain risk factors, among them UV radiation exposure, genetic influences, oral contraceptives and other estrogen-progesterone therapies, pregnancy, thyroid dysfunction, cosmetics, and medication.
Based on currently available research, male melasma may be associated with many of the same risk factors and pathogenic features that influence lesion formation and characterize lesion morphology in afflicted females. Although some risk factors are preserved across genders, the weight of influence of the different risk factors appears to vary considerably between males and females. Demographic studies noted sun exposure (66.6%) and familial predisposition (70.4%) as the two most significant etiologic factors in male patients, a finding later confirmed (48.8% and 37%, respectively). These are largely in concordance with percentages recorded in female melasma patients.
Hormonal influences most likely play minor roles in men, as few men use hormonal therapy, unlike in females, where contraception use and pregnancy are risk factors. Despite this fact, there is preliminary evidence of a hormonal component that may influence the interplay of factors leading to lesion formation in men. A small study of 15 male melasma patients in India noted significantly elevated levels of luteinizing hormone and follicle-stimulating hormone with concomitant depression of serum testosterone in affected individuals. Luteinizing hormone and follicle-stimulating hormone levels in these patients were thought to be physiologically elevated through a natural response to low testosterone levels, indicating the malfunction rests at the level of the sexual organs. These findings suggest a component of subtle testosterone resistance, perhaps a male analog to a subtle ovarian resistance with similar characteristics previously reported in women with melasma.
Histopathologic evaluation of melasma lesions in male patients reveals consistent patterns of increased vascularity and elevated c-kit and stem cell factor expression in lesional skin compared to control samples taken from adjacent unaffected skin. Levels of stem cell factor expression in male melasma patients are in excess of those demonstrated in affected females, perhaps suggestive of the increased UV exposure necessary to induce lesion formation in the absence of a permissive hormonal milieu. However, the size of each cohort (eight men with melasma, ten women with melasma, and five men and women each with solar lentigines) in this report was too small to conclusively make this determination.
Clinical features and treatment modalities
Regardless of the exact mechanism behind the development of melasma, the resultant tan-to-dark-brown macules and patches on the face are similar in both genders. Epidemiologic breakdown of melasma patterns in male patients has received little attention in the literature. Sarkar, Jain et al. noted centrofacial and malar patterns in their cohort (48.39% and 51.61%, respectively) with no patients demonstrating mandibular patterns, whereas Sarkar, Puri et al. noted malar (61%), centrofacial (29.3%), and mandibular (9.3%) patterns in their patients. Although these results appear to be consistent with the distribution of patterns reported in female patients, much larger male cohorts are necessary to generate more meaningful data.
The treatment of melasma in all patients involves multiple therapeutic modalities, including broad-spectrum sun protection, topical formulations, chemical peels, lasers, light sources, or a combination of the above. These therapies appear equally effective irrespective of gender. Details regarding the mechanism, side-effect profile, and utility of different treatments are discussed in greater detail elsewhere in the literature.
Conclusion
Melasma is an acquired pigmentary disorder of complex and likely multifactorial etiology with significant adverse effects on afflicted patients. It affects both men and women, albeit unequally. In fact, as a result of this uneven impact, melasma in men has received comparatively little investigation. Based on current knowledge, it appears that melasma in men is influenced to similar degrees by the same risk factors as in affected females, with the likely exception of hormonal effects. Ultimately, further research in men with melasma is necessary to better delineate the unique clinical and pathogenic features in this subset of patients.