INTRODUCTION: Identification of the underlying causes of idiopathic cutaneous hyperchromia at the orbital region (ICHOR) is crucial in selecting the best therapeutic management.
OBJECTIVE: This study aims to evaluate the histopathological changes of different types of ICHOR.
METHODS: Forty-nine healthy volunteers were classified into (i) hyperpigmented (ii) hypervascularised or (iii) tear trough groups. Melanin deposit, hemosiderin deposit, blood vessels dilatation, perifollicular inflammation, structures of epidermis ridges were assessed histologically. Its association with the type of ICHOR was analysed using Pearson's chi-squared test.
RESULTS: A total of 53.1% ICHOR subjects was diagnosed as hyperpigmented, 16.3% as hypervascularised and 30.6% as tear trough and. Pearson's chi-squared test showed that hyperpigmented group associated with high level of melanin deposit (p<0.05), and invagination of melanin pigments into the dermal layer (p<0.05). Hypervascularity was associated with dilated blood vessel (p<0.05). Interestingly, tear trough was associated with dilated blood vessels (p<0.05) and perifollicular inflammation (p<0.05).
CONCLUSION: Each type of ICHOR showed distinct histopathological changes, selection of precise targeted therapy is important in treating ICHOR effectively.

Keywords: Hyperpigmentation; Histology; Melanosis

INTRODUCTION: Identifying the causes of periorbital hyperpigmentation is crucial in selecting the best treatment. The identification of transcriptional profiles that may be related to hyperpigmentation around the eye area could contribute to a new approach in the treatment of periorbital hyperpigmentation – the gene therapy.
OBJECTIVE: This study aims to assess the transcriptional profile of melanogenesis, and genes related to enzymatic antioxidants in skins with periorbital hyperpigmentation.
METHODS: Based on clinical evaluation, 49 healthy volunteers were classified with or without periorbital hyperpigmentation. Genetic profiles of melanogenesis-related genes: microphthalmia-associated transcription factor (MITF), pro-opiomelanocortin (POMC), melanocortin 1 receptor (MC1R), tyrosinase (TYR), tyrosinase 1-related protein (TYRP1), and intracellular antioxidants - glutathione reductase (GR), glutathione peroxidase 1 (GPx-1), glutathione s-transferase (GST-1) - were determined by the polymerase chain reaction technique in real-time.
RESULTS: MITF, TYR, and TYRP1 gene expressions were significantly higher in the periorbital hyperpigmentation group (p<0.01). GR, GPx-1, and GST-1 gene expressions were comparable between the groups with and without periorbital hyperpigmentation.
CONCLUSIONS: The results of this study suggest that MITF is the primary regulator of melanin deposition in skins with periorbital hyperpigmentation. Up-regulated MITF is closely associated with increased TYR and TYRP1.These findings are essential in proposing a new therapeutic approach in the treatment of periorbital hyperpigmentation.

Keywords: Hyperpigmentation; Melanins; Microphthalmia-associated transcription factor