The pathogenesis of Demodex folliculorum (hair follicular mites) in females with and without rosacea.

In rosacea patients (ages 11-50 years old) 44% were infested with D. folliculorum as compared to normal controls (23.0%). The difference was significant. The mean +/-SD of mite density ranged between 13.2+/-0.9 to 18.2+/-1.2 as compared to normal controls with mite density ranged between 1.4+/-0.25 to 2.4+/-0.3. Demodex infestation in rosacea patients was 66.1% in squamous, 66.7% in erythemato-telangiectate and 83.3% in papulo-pustular rosacea. The highly infested site was check (27.3%) with mean mite density of 25.3+/-1.3, followed by the area around the orbit (23.4%) with a density of 19.0+/-1.2, the area around the nose (19.5%) with mite density of 7.1+/-1.5, then chin (15.6%) with a density of 8.2+/-1.4 and lastly the area around the mouth (14.1%) with a mite density of 14.2+/-1.3. Undoubtedly, infestation with D. folliculorum particularly in large number causes rosacea.