Association Between Melasma And Thyroid Dysfunction:A Hospital-Based Case-Control Study

Abstract

Introduction: Melasma is a common acquired hyperpigmentary disorder primarily affecting sun-exposed areas, predominantly in women of reproductive age. Thyroid dysfunction has been proposed as a potential endocrine trigger; however, data from Nepalese populations remain limited.

Objectives: This study aimed to determine the prevalence of thyroid dysfunction in melasma patients compared to matched controls, and to assess its association with clinical parameters of melasma.

Methods: A 1:1 frequency-matched case-control study was conducted at Nepalgunj Medical College and Teaching Hospital, Kohalpur, Nepal (65 melasma cases, 65 controls). Serum TSH was measured by ECLIA. Analyses included Fisher’s exact test, Mann-Whitney U test, Kruskal-Wallis test, and Spearman’s rank correlation.

Results: The groups were comparable in age (median 30 years; p = 0.883) and sex (p = 1.000). Thyroid dysfunction was detected in 17/65 cases (26.2%) versus 4/65 controls (6.2%); OR 5.40 (95% CI 1.71–17.11; p = 0.003). Hypothyroidism accounted for 94.1% of cases with thyroid dysfunction. Median serum TSH was 2.97 mIU/L in cases versus 2.59 mIU/L in controls (p = 0.095). Centrofacial and malar distributions each comprised 44.6% of cases. Thyroid dysfunction was exclusive to female cases (17/56, 30.4%; p = 0.098). No significant correlation was identified between serum TSH and melasma duration (r = −0.077, p = 0.543).

Conclusions: Thyroid dysfunction was significantly more prevalent in melasma patients versus controls (OR 5.40; 95% CI 1.71–17.11; p = 0.003), with hypothyroidism predominating (94.1%). These findings highlight thyroid dysfunction as a relevant systemic co-morbidity in melasma, warranting further multicentre studies.