Self-reported skin colour and erythemal sensitivity vs. objectively measured constitutive skin colour in an African population with predominantly dark skin

Abstract

BACKGROUND : Skin colour is an important factor in skin-related diseases. Accurate determination of skin colour is important for disease prevention and supporting healthy sun behaviour, yet such data are lacking for dark skin types. METHODS : Self-perceived, natural skin colour and sun-skin reaction were compared with objectively-measured skin colour among an African population with predominantly dark skin. Unexposed skin of 556 adults (70.1% Black) was measured with a reflectance spectrophotometer to calculate an Individual Typology Angle (°ITA). Participants reported self-perceived skin colour and erythemal sensitivity. RESULTS : There was a strong, positive monotonic correlation between self-reported and measured skin colour (Spearman =0.6438, p<0.001), but only a weak correlation between self-reported erythemal sensitivity and measured skin colour (Spearman =0.2713, p < 0.001). Self-report biases in under- and over-estimation of skin colour were evident. Many participants with „dark brown‟ and „black‟ skin had difficulty classifying erythemal sensitivity. CONCLUSIONS : In Africa, self-reported skin colour could potentially be used in lieu of spectrophotometer measurements, but options for questions on sunburn and tanning require suitable adjustment. Our study provides evidence of range in °ITA values among residents in Africa and reinforces previous results that self-report may be reliable for determining skin colour, but not erythemal sensitivity, for dark skin individuals. (word count: 199 excluding section headings)