An evidence-based, peer-reviewed journal for practicing clinicians in the field of dermatology
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54 JCAD JOURNAL OF CLINICAL AND AESTHETIC DERMATOLOGY February 2018 • Volume 11 • Number 2 R E V I E W Brazil, Singapore, and India have shown a difference as high as 39:114, 21:115, and 6:1, respectively. 13 In Puerto Rico, a study by Vazquez et al 16 found that men made up only 10 percent of the cases of melasma. In contrast to this low incidence of melasma in Caucasian men, the researchers found that melasma was more commonly reported in men of Hispanic, Asian, and Indian origin. 1,2,4 In the study by Pichardo et al 6 , which included Hispanic men with melasma, data were pooled from three studies: one examining 25 poultry workers, one examining 54 farm workers, and one examining 300 Hispanic farm workers. The prevalence of melasma was 36 percent, 7.4 percent, and 14 percent in the three study groups, respectively. There was a mean prevalence of 14.5 percent, larger than the prevalence of melasma reported in a random sampling of Hispanic women (8.2%). 10 The difference could be partially due to the difference in study design between the two studies; in the study on Hispanic women by Werlinger et al, 10 melasma was self-diagnosed by patients over telephone interviews, which could result in inaccurate reporting. 10 Therefore, further studies are required to better quantify the sex-specific prevalence of melasma among the Hispanic population. In Indian patients, two studies show a higher prevalence of melasma in men (25.8% [n=120] and 20.5% [n=200]). 5,17 This increased prevalence among Indian men compared to Caucasian men could be attributed to their darker complexion and the tropical Indian climate. ETIOPATHOGENESIS The exact etiology of melasma is not known. However, some of the most common factors include sun exposure, hormonal influences, and genetic susceptibility. Other less common causes include cosmetics, photosensitizing drugs, food items, thyroid diseases, hepatopathies, ovarian tumors, parasitic infestations, and stressful events. 13,14,18,19 Melasma is caused by a complex interplay of environmental factors in a genetically predisposed individual. The etiological factors causing melasma in men are likely the same as those implicated in women, except for certain differences (Table 1). Genetic etiology of melasma in terms of familial predisposition is a notable risk factor. The occurrence of melasma has been described in a pair of identical twins, 20 suggesting a common genetic component. This has been confirmed in various studies, with positive family history being present in 10 to 70 percent of patients in studies on melasma among Iranian, Singaporean, Hispanic, and African- American populations. 18,21,22 In a multicenter study (9 centers across the world) by Ortenne et al, 18 48 percent of 324 patients with melasma reported family history in at least one relative, with 97 percent being first-degree relatives. In other studies, the prevalence varied from 56 percent in Brazil (n=3012) to 33 percent in India (n=312) and 10 percent in Singapore (n=205). 23,24 A majority of these studies focused on women and there are only a few studies that document the presence of family history in men with melasma. However, a family history was reported in among a large percentage of male patients in the study by Vazquez et al (70.4%). In this study, family history of melasma was reported among close family members (e.g., mother, siblings, aunts, and uncles) however, none of the patients reported melasma in the father. 16 In an Indian study, 39 percent of men had a family history of melasma, compared to 20.1 percent in women (Table 2). 5 Further, a study by Keeling et al, documented the presence of family history of melasma in a first- or second- degree female relative in all five male patients, TABLE 1. Etiological factors and clinical features of melasma in men and women 5 CHARACTERISTICS MEN (N=41) WOMEN (N=159) P-VALUE AGGRAVATING FACTORS Sunlight exposure 20 (48.8%) 38 (23.9%) <0.05* Family history of melasma 16 (39.0%) 32 (20.1%) <0.05* Phenytoin 3 (7.3%) 2 (1.3%) NA Pregnancy 0 72 (45.3%) NA Oral contraceptives 0 31 (19.4%) NA History of Chronic illness (Post typhoid period, thyroid disorder, inflammatory bowel disease) 5 (22.2%) 32 (20.1%) >0.05* Application of mustard oil 18 (43.9%) 50 (31.4%) >0.05* AGE (YEARS) Mean age 33.5 31.5 >0.05** Range of age 19-53 20-45 NA DURATION Duration of melasma (years) 0.1-8.0 0.6-7.0 NA Mean duration of melasma (years) 3.5 3.1 >0.05** CLINICAL PATTERN OF MELASMA Centrofacial 12 (29.3%) 81 (51.0%) <0.001*** Malar 25 (61%) 39 (24.5%) <0.001*** Mandibular 4 (9.7%) 39 (24.5%) <0.001*** WOOD LIGHT EXAMINATION Epidermal 28 (68.3%) 90 (56.6%) 0.85*** Mixed 9 (22.0%) 44 (27.7%) 0.85*** Dermal 4 (9.7%) 25 (15.7%) 0.85*** HISTOPATHOLOGICAL EXAMINATION Epidermal 10/20 (50%) 25/40 (62.5%) - Mixed 9/20 (45%) 12/40 (30%) - Dermal 1/20 (5%) 3/40 (7.5%) - *Z-test for testing difference between two different sample proportion; **Independent sample t-test ; ***χ 2 -test of significance; <0.001 highly significant; <0.05 significant; NA: not applicable for significance testing Acknowledged from Sarkar R, Garg S. Melasma in men. In: Melasma: A Monograph.1st ed. Sarkar R (ed). New Delhi, India: Jaypee Brothers Medical Publishers (P) Ltd; 2015:80–84