An objective skin‐type classification based on non‐invasive biophysical parameters

Abstract

Background Despite the invention of various non-invasive bioengineering tools, skin-type analysis has largely been based on subjective assessments. However, advancements in the functional cosmetic industry and artificial intelligenceassisted dermatology are creating a greater demand for an objective skin-type classification system.Objectives To propose an objective skin-type classification system solely based on non-invasive, bioengineering devices; provide reference values applicable to the Korean population; and compare our reference values with those of published studies. Methods Biophysical parameter measurements were obtained from the 2018 International Skin Characteristics Data Bank Project conducted by the Foundation of Korea Cosmetic Industry Institute. The participants were 434 healthy South Korean adults. Each participant was assessed using eight bioengineering devices (Tewameter â , pH-meter â , Corneometer â , Sebumeter â , Cutometer â , Spectrophotometer â , PRIMOS â lite, and Janus â ). The measurements were divided into tertiles to determine reference points.Results Our objective skin-type classification consists of five main categories (sensitivity, hydration, oiliness, elasticity, and skin tone) and five corresponding subcategories (erythema, roughness, pores, wrinkles, and pigmentation, respectively). Each skin type was assigned based on the reference point of the biophysical parameter, which was established as the tertile value associated with 'unfavourable' skin characteristics. Individuals were categorized as having sensitive skin when the TEWL scores were over 18.0 g/m 2 /h or the pH was over 5.45; dehydrated skin when the corneometric value measured below 47.17 A.U.; oily skin when the sebumetric value exceeded 70 lg/cm 2 ; and loose skin when the cutometric R 2 value was below 0.68 E/mm. ConclusionsThis study is the first to provide a comprehensive skin-type classification system based solely on noninvasive biophysical parameters. As measurement data accumulate, the reference points will progress to become more accurate, and they will be subdivided according to gender, age, and ethnic group. Therefore, our classification system serves as a basis for artificial intelligence-based skin-type analysis.

A comprehensive comparison of facial skin hydration based on capacitance and conductance measurements in Chinese women

“…Diagram representing the relative values (0%–100%) of the Skicon (blue line) and the Corneometer (red line) for the individual 30 facial test sites [1–30]. [Colour figure can be viewed at wileyonlinelibrary.com]…”

“… Diagram representing the relative values (0%–100%) of the Skicon (blue line) and the Corneometer (red line) for the individual 30 facial test sites [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ]. [Colour figure can be viewed at wileyonlinelibrary.com ] …”

“…In this observational study, we compared the continuous skin hydration maps generated with a Corneometer and a Skicon independently in Chinese women graded with moderately dry and rough facial skin. We chose a cutoff for normal skin at 48 AU for the Corneometer which is slightly higher for forearm data and slightly lower for other facial data reported by others [ 23 , 24 ] but it was virtually identical to that of Seo et al [ 25 ]; for a review on recent data, see [ 26 ]. This equates to 132 μS for the Skicon.…”

Optimisation of skin phototype classification

“…Combining several skin evaluation tools, Seo et al developed an objective method of classifying skin type, which involved assessing skin tone, sensitivity, hydration, oiliness and elasticity (Seo et al, 2022). Here, a spectrophotometer was used to assess skin erythema and sensitivity.…”

Explore highly relevant questions in the Baumann skin type questionnaire through the digital skin analyzer: A retrospective single‐center study in South Korea

“…Everybody has his or her own skin characteristics depending on race, gender, and age, where its diversity is manifested not only in dermatology diseases but also in various skin profiles that are commonly described as oily, wrinkle, or sensitive, etc 1–3 . Several attempts have been made to classify skin characteristics, such as using devices that measure its biophysical parameters 4–9 . However, such an approach has drawbacks that it requires expensive equipment and lacks clear reference points to categorize types of skin.…”