Analysis Of Demodex Infection In Patients With Rosacea And Determination Of Their Facial Skin Physiology Index

Background:Rosacea is a chronic inflammatory skin disease characterized by the appearance of erythema, telangiectasia, papules, and pustules affecting the central area of the face. Its etiology is unknown. Demodex has been reported in rosacea in a number of clinical studies. Facial excessive sebum secretion is the predisposing factor of infection demodex, but lack of means objective assessment of the oil secretion.Objective:1. To determine the demodex density of the face in rosacea. and its physiology index of patients with rosacea. 2. To characterize the skin physiology functiom of patients with rosacea and to facilitate its treatment and daily skin care.Methods:During May to September 2009, Sixty-five patients with rosacea and sixty healthy human controls from the Second Hospital of Lanzhou University were enrolled into this study. With the skin surface biopsy technique, the samples was obtained from three facial sites (forehead, nose and chin) of the patients and the controls. The mite count was the mean value of the three facial sites, caculated as the sum of mites/cm2. A portion of each specimen was mounted in 10% KOH and examined microscopically for the presence of mites. Sebumeter was used to detect the sebum secretion and pH to the patients and the controls.Results:The prevalence and mean demodex density in the rosacea groups were significantly higher than that in the healthy controls(P<0.05). The mean demodex density in the papulopustular subtype and phymatous subtype were significantly higher than that in erythematotelangic subtype, respectively. (P<0.05). The mean demodex density in the papulopustular subtype and phymatous subtype were no significantly difference(P>0.05). The level of sebum secretion in patients with rosacea with infection demodex was higher than that in the non-infection demodex health controls. However, the level of skin pH was no significant difference between the patients and controls.Conclusion:The facial demodex infection is one of the pathogenic factors of rosacea. Facial excessive sebum secretion is the predisposing factor of infection demodex.