Multiple senile lentigos of the face, a skin ageing pattern resulting from a life excess of intermittent sun exposure in dark-skinned caucasians: a case-control study

BACKGROUND: Different patterns of skin ageing can be described depending on the predominant lesions, i.e. wrinkles, laxity, atrophy, senile lentigos (SLs), etc. They may correspond to different epidemiological contexts. OBJECTIVES: To identify and assess the epidemiological factors for a skin ageing pattern characterized by a high density of SLs on the face, or 'lentigo ageing pattern' (LAP). METHODS: An age- and sex-matched case-control study was conducted in individuals aged between 60 and 80 years, comparing cases (n = 118) with a very high number of SLs on the face for their age, and controls (n = 118) with no or very few SLs for their age. The cases and controls were recruited in two hospitals. RESULTS: In univariate and multivariate analysis, LAP was associated with skin types III and IV, with frequent sunburns, and with the part of the lifetime cumulative sun exposure which was received during vacations. Conversely, there was no link with the occupational and everyday exposures and the total cumulative exposure. LAP was associated with multiple solar lentigos of the upper back. No relationship was found with postmenopausal hormonal therapy, number of naevi, or freckles. CONCLUSIONS: Different epidemiological factors may account for the different skin ageing patterns. LAP seems to develop preferentially in dark-skinned caucasians who have repeatedly received intermittent and intense sun irradiations throughout their life, and have often developed solar lentigos on the upper back earlier in life, whereas the 'prominent wrinkling' pattern is known to affect light-skinned people and smokers with a life excess of continuous exposure.