Background: Studies on facial hyperpigmentation across different facial units are limiting.
Objectives: We sought to analyze melanin pigment images to observe facial pigmentary demarcation lines and suggest patterns for facial hyperpigmentation of normal individuals.
Methods: Three-dimensional facial melanin pigment images of 173 volunteers with Fitzpatrick skin types II-IV were obtained and analyzed for the presence of pigmentary demarcation lines and hyperpigmentation. Pigmentation severity was assessed for each of the fourteen facial pigmentary units and the volunteers were categorized into three hyperpigmentation types - dark spot, photoaging, and post-inflammatory hyperpigmentation.
Results: The most common pigmentary demarcation line was Type F (27.7 %) and a novel pigmentary demarcation line, Type I, was the second most common (19.1 %). Nasal was the most hyperpigmented pigmentary unit, and eyebrow was the least hyperpigmented. The dark spot type was observed in about 40 % to 60 % of subjects across all age groups. The photoaging type was observed from the age groups of 40s through 60s and the prevalence showed a positive correlation with age. The PIH type was observed in 56 % of the subjects in 20s, and the prevalence constantly decreased with the increasing age.
Conclusion: This study analyzed melanin pigment images, to observe a novel facial demarcation line and suggest three facial hyperpigmentation types among individuals with Fitzpatrick skin types II-IV