Reflectance confocal microscopy for monitoring the density of Demodex mites in patients with rosacea before and after treatment
Summary
Background
Demodex mites seem to serve as a pathogenic trigger in many Demodex-associated diseases such as rosacea. In facial skin of patients with rosacea significantly higher numbers of Demodex mites have been shown compared with healthy controls. Reflectance confocal microscopy (RCM) allows the detection and quantification of Demodex mites in vivo noninvasively. It is hypothesized that a reduction of Demodex mites under rosacea therapy can be monitored by RCM.
Objectives
To use RCM to monitor the density of Demodex mites in patients with rosacea before and after treatment.
Methods
In 25 patients with facial rosacea RCM was performed before and after therapy. Mosaics of 5 × 5 mm2 and 8 × 8 mm2 were scanned, and the total numbers of mites per follicle and per area were counted, along with the number of follicles per area.
Results
In all patients Demodex folliculorum could be detected and quantified using RCM. RCM showed significant differences pre- and post-treatment (P = 0·0053 for 5 × 5 mm2 and P < 0·001 for 8 × 8 mm2). The mean numbers of mites per follicle were 0·63 (range 0·16–2·28) per 8 × 8 mm2 area and 0·70 (range 0·11–2·20) per 5 × 5 mm2 area before treatment, and 0·41 (range 0·074–1·75) and 0·51 (range 0·094–1·70), respectively, after treatment. The corresponding mean numbers of mites were 155 (range 45–446) and 86·2 (range 12–286), respectively, before treatment and 96·2 (range 18–363) and 58·5 (range 12–230), respectively, after treatment.
Conclusions
By RCM, a reduction in the density of Demodex mites in facial skin of patients with rosacea under therapy, correlating to clinical improvement, can be quantified and monitored noninvasively. Possible reasons for this therapeutic effect are discussed.
