Image based quantification method reveals differential patterns of lip desquamation associated with age and sex

TL;DR

This study introduces an image-based method to quantify lip desquamation and finds age and sex differences in lip skin flaking patterns.

Contribution

The paper presents a novel image analysis technique for quantifying lip desquamation and reveals new age- and sex-specific patterns.

Findings

The image-based method strongly correlates with visual assessments of lip desquamation (r = 0.715).

Lip desquamation decreases with age in males and females over 38, but increases in females under 38.

Sex differences in lip desquamation are most pronounced in individuals in their 20s.

Abstract

The rough surface of lip skin is a dermatological and aesthetic issue that affects facial appearance. While several studies have addressed this common problem, none of them have exclusively utilized image analysis techniques. In this study, we aimed to quantify lip desquamation from facial images in a total of 55 participants and compare the results to those obtained from the tape-stripping method. The central region of the lower lip was extracted from each facial image, and global thresholding was applied using the threshold value T, which is defined as Mean + 2.5 SD. In this equation, Mean and SD represent the average and standard deviation of each grayscale values within the image, respectively. The desquamation rate was calculated as the proportion of pixels corresponding to desquamated flakes within the analyzed region. We found that our approach accurately represented the lip surface states, with a strong correlation with visual assessment (VA) scores (r = 0.715, p < 0.001). To investigate the relationship between lip desquamation and age, we further analyzed the facial images of 1,000 individuals. A gradual decline in lip desquamation with age was observed in males (r = -0.151, p < 0.001) and females over 38 years (r = -0.133, p < 0.05). In contrast, the variation of lip desquamation among females under the age of 38 showed an increasing trend (r = 0.234, p < 0.01). It is notable that the most pronounced differences between sexes were only observed in individuals in their 20s (p < 0.001). Such results imply that the characteristics of epithelial layer of lip can be segmented based on chronological age and sex. These notable changes in lip desquamation were discovered for the first time in this study. Given the current ease of acquiring image data, our image-based method has the potential to advance the lip skin research.

The online version contains supplementary material available at 10.1038/s41598-025-89264-x.

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