Demodex mites are among the most prevalent human parasites. While commonly found on healthy individuals, an overpopulation of this arachnid resident of human skin triggers demodicosis, a neglected yet widely prevalent disease with considerable skin and eye morbidity. Despite its health impact, demodicosis remains overshadowed by other common skin diseases. This neglect has significant consequences for individual and public health, which require a paradigm shift in our understanding and management of this ubiquitous ectoparasite. We reviewed the literature to re-evaluate the pathogenicity of the Demodex mite, paying particular attention to the primary risk factors-immune dysregulation, altered microbiota, and concurrent infections-that may contribute to pathogenicity. We discuss the challenges in combating neglect of demodicosis and provide updates on various impediments in achieving this goal. We explore the issues and research gaps in various domains such as those related to parasite biology, pathogenesis, diagnosis, treatment, prevention and control. We present potential solutions and outline future prospects for tackling this important disease. Finally, we hope to catalyze greater attention and investment for this neglected public health issue.

Raising awareness of Demodex and demodicosis and its major contribution to human diseases requires a multidisciplinary approach. Efforts to prioritize its place on the global health agenda, invest in research, improve diagnostic tools, and develop new treatment strategies will lead to improved public health outcomes and a higher quality of life for those affected.

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.

To use RCM to monitor the density of Demodex mites in patients with rosacea before and after treatment.

In 25 patients with facial rosacea RCM was performed before and after therapy. Mosaics of 5 × 5 mm(2) and 8 × 8 mm(2) were scanned, and the total numbers of mites per follicle and per area were counted, along with the number of follicles per area.

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 mm(2) and P < 0.001 for 8 × 8 mm(2)). The mean numbers of mites per follicle were 0.63 (range 0.16-2.28) per 8 × 8 mm(2) area and 0.70 (range 0.11-2.20) per 5 × 5 mm(2) 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.

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.