Chromametric quantification of pigmentary changes in the solar lentigo after sunlight exposure.

The purpose of this study is to compare by chromametric analysis the changes seen in normal skin and solar lentigos after exposure to sunlight. The color measurements were made with a Minolta CR200 chromameter and expressed in the Lab* system, which allows a color to be quantified according to 3 axes: white-black (L*), red-green (a*) and yellow-blue (b*). In order to better assess the sensitivity of physiological mechanisms involved in this pigmentation, we chose the weakest conditions of sunlight: the first series of measurements were made at the end of the winter (March) on areas rarely exposed for several months, and the second measurement was made 2 months later before the first intense summer solar exposure. Solar lentigos underwent a significant change in pigmentation, with a darkening of these lesions and an increase in the red and yellow color components. The pigmentation of healthy skin adjacent to these lentigos remained unchanged.