Acne cosmetica revisited: a case-control study shows a dose-dependent inverse association between overall cosmetic use and post-adolescent acne.
Case-control studies to support the concept of acne cosmetica are lacking. To examine the association of post-adolescent acne with the use of cosmetics and cosmetic procedures. 910 post-adolescent patients with acne and an equal number of matched controls were studied for exposure to cosmetics and cosmetic procedures. A cumulative cosmetic exposure index was stratified into four quarters of increasing exposure. Comparison of different cumulative exposure categories with the lowest exposure category (multivariate analysis, logistic regression) showed that the odds ratios, which were always <1, progressively declined as cosmetic exposure increased [odds ratios (95% confidence intervals): 0.679 (0.501-0.922), 0.355 (0.258-0.487), 0.307 (0.217-0.433)]. However, some individual cosmetics had odds ratios >1. Overall cosmetic use was negatively associated with post-adolescent acne. The term 'acne cosmetica' is appropriate in the sense that some cosmetics may cause acne.