Site, gender and age variation in normal skin colour on the back and the forearm: tristimulus colorimeter measurements.

Abstract

To study whether anatomical location and age and gender of subjects had any influence on the objective skin colour measurements. Baseline colour in prone position was measured with the Minolta ChromaMeter® in the upper, middle and lower level of the upper back and on the forearm of 168 volunteers. These two sites are commonly used in skin testing. Higher basal a* and lower basal L* levels were found on the upper scapular region compared to the lower scapular region and the subscapular region. The basal b* level showed no variation relative to site. The basal a* and the basal b* levels were lower on the forearm compared to the upper back while the basal L* level was higher. Females above 65 years showed a less coloured skin with lower values as compared to those of younger age. Females were found to have a generally lower basal a* level than males both on the upper back and forearm skin. These relatively major differences and sources of variation have to be considered when planning irritancy studies where colour differences between erythema and normal skin is used.