Quantifying Erythema and Skin Tone Variation in Cutaneous Rashes: A Colorimetric Approach.

Area of Science:

• Dermatology
• Colorimetry
• Skin Physiology

Background:

• Accurate erythema assessment is crucial in dermatology but challenging across diverse skin tones.
• Traditional visual methods like the Fitzpatrick scale are limited, especially in darker skin.
• Objective colorimetric tools offer quantitative measurements but need validation across skin types.

Purpose of the Study:

• To evaluate the performance of objective colorimetric tools for erythema assessment in diverse skin tones.
• To compare colorimetric measurements with visual assessment and baseline skin characteristics.
• To explore the utility of colorimetry in diagnosing and monitoring skin conditions.

Main Methods:

• A cross-sectional study involving 44 dermatology outpatients with rashes.
• Measurement of erythema index (EI), melanin index (MI), Individual Typology Angle (ITA), and CIELAB values at baseline and rash sites.
• Statistical analysis including paired t-tests, Pearson correlations, and ANOVA across Fitzpatrick phototypes and ITA categories.

Main Results:

• Erythema was significantly elevated at rash sites compared to baseline.
• Higher melanin levels correlated with lower ITA and skin lightness.
• Baseline erythema did not correlate with rash erythema; darker ITA categories showed higher erythema levels.

Conclusions:

• Colorimetric tools are supported for use across all skin tones in clinical dermatology.
• Objective measurements improve diagnostic accuracy and treatment personalization, promoting equity.
• Future longitudinal studies are needed to assess treatment efficacy using colorimetry.