INTRODUCTION
Melasma is a commonly acquired pigmentation disorder classically favoring young women of color or those with exacerbating factors, such as hyper-estrogen states.1 In this study, we utilized a large global health research network database from 108 health care organizations (TriNetx) to quantify the associations between race, ethnicity, and comorbidities with the prevalence of melasma. Through an enhanced understanding of those most prone to this dyschromia, dermatologists can better stratify potential surveillance and treatment plans.
MATERIALS AND METHODS
We identified the cohort of all patients diagnosed with melasma from the TriNetx database and subsequently generated a control cohort of age, sex, and race-matched patients without melasma. ICD-10 codes were used to identify the prevalence of previously reported comorbidities in both the melasma and control populations: allergic rhinitis, anticonvulsants, atopic dermatitis, diabetes, hormonal contraceptives, hypertension, hypothyroidism, lupus, malignancy, rosacea, skin cancer, and smoking. Odds ratios were subsequently generated and confirmed with Fisher's exact tests.
RESULTS
A total of 41,283 patients with melasma (93% female, mean [SD] age 48.8 [12.6] years) were identified (Table 1). The most frequently associated risk factors included hypertension (25%) and hormonal contraception (24%). Rosacea (OR=5.1), atopic dermatitis (OR=3.3), lupus (OR=2.5), history of skin cancer (OR=2.5), and history of internal malignancy (OR=2.1) possessed the highest odds ratios for development of melasma (all P<0.01) (Table 2). A statistically significant association was identified for melasma in Asian or Other/Unknown races (OR=2.0 and OR=1.7, P<0.01), as well as Hispanic ethnicity (OR=1.3, P<0.01). White, Black/African American, and Not Hispanic groups all revealed slightly lower odds (all 0.8, P<0.01) (Table 2).
DISCUSSION
This latest update on the association of skin of color and comorbidities of melasma further supports the findings from a prior epidemiologic study reporting preference in melanized phenotypes (Fitzpatrick skin type III-V), but less so in extreme skin types (I, II, VI).2 The melasma cohort revealed very high associations with rosacea and atopic dermatitis, possibly related to increased blood flow and overactive mast cells present in both conditions, emphasizing the importance of treating concurrent inflammatory environments.3,4
