Association of Rosacea with Demodicosis

There are controversial reports about the role of Demodex mites in pathogenesis of acne rosacea. The aim of this study was to examine the relationship between the presence and number of Demodex mites and the pathogenesis of rosacea. In this case-control study, the prevalence of Demodex mites was studied in facial biopsy of 75 patients with acne rosacea as case group, and in 75 patients with discoid lupus erythematosus and 75 patients with actinic lichen planus as control groups. The prevalence of Demodex mites in patients with acne rosacea (38.6%) was significantly higher than the patients with discoid lupus erythematosus (21.3%) and actinic lichen planus patients (10.6%) (P < 0.001). This study suggests that Demodex mites may play a role in pathogenesis of rosacea but it is not clear whether rosacea merely provides a suitable environment for multiplication of mites, or the mites play a role in the pathological changes.