Objective spectrometric measurement of keloid color in the East Asian population: Pitfalls of subjective color measurements

Abstract

Background: Keloids are characterized by the formation of excessive scar tissue that extends beyond the area of the initial wound. Keloid redness is due to angiogenesis and chronic inflammation and is an important indicator of the severity of the lesion and the effectiveness of treatment. Methods: The color of 33 untreated keloids from 30 patients was measured with a narrow-band reflectance colorimeter. The erythema and melanin levels in the keloids (Ek and Mk, respectively) were recorded with control data obtained from the flexor aspect of the forearm (Ec and Mc, respectively). The keloid color was also evaluated subjectively. Results: The Ek or Mk values did not vary significantly according to symptom intensity, scar region, patient age, and patient sex. Younger patients (<40 years) and female patients had significantly higher Ek/Ec ratios than did older patients and male patients, respectively. Subjective keloid redness evaluations distinguished keloids with high Ek/Ec ratios from keloids with low Ek/Ec ratios (P<0.0001) but could not distinguish keloids with high Ek from keloids with low Ek. Conclusions: Subjective evaluations of keloids in Japanese subjects reflected Ek/Ec ratios, which were strongly affected by variation in background skin color. The subjective assessment of the color of keloids or other skin disorders should be performed with caution in Asian populations.