MELANIN CONTENT AND DISTRIBUTION IN THE SURFACE CORNEOCYTE WITH SKIN PHOTOTYPES

An individual's sensitivity to sunlight is traditionally assessed by t he Boston or Fitzpatrick classification of skin type, The ability to t an depends, to some degree, on the melanin content of the epidermis, I n the study reported here, surface corneocytes in exposed skin and une xposed skin have been assessed using a surface stripping slide mountin g technique and an Optomax V image analyser, with which the percentage of corneocyte area occupied by melanin granules has been taken as the melanin content index (MCI). There was a significantly different MCI between different skin types for both exposed (P < 0.0001) and unexpos ed (P < 0.0001) areas using the Kruskal-Wallis one-way ANOVA test, The re was also a positive significant correlation between MCI and skin ty pes II-VI in both exposed (r = 0.95, P < 0.001) and unexposed areas (r = 0.89, P < 0.005), Image analysis also demonstrated that the number of melanin grannies in surface corneocytes was significantly higher in the exposed area compared with the unexposed area, for skin types II, III, IV, V and VI. Melanin cap-like structures were also observed in exposed corneocytes and heavily pigmented skin contained larger melani n particles than fairer skin, The results indicate that an individual' s skin phototype and melanin content, assessed by image analysis, have a significant correlation.